Records |
Author |
Ding, F.; Li, B.; Akopian, N.; Perinetti, U.; Chen, Y.H.; Peeters, F.M.; Rastelli, A.; Zwiller, V.; Schmidt, O.G. |
Title |
Single neutral excitons confined in AsBr3 in situ etched InGaAs quantum rings |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of nanoelectronics and optoelectronics |
Abbreviated Journal |
J Nanoelectron Optoe |
Volume |
6 |
Issue |
1 |
Pages |
51-57 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
Abstract |
We observe the evolution of single self-assembled semiconductor quantum dots into quantum rings during AsBr3 in situ etching. The direct three-dimensional imaging of In(Ga)As nanostructures embedded in GaAs matrix is demonstrated by selective wet chemical etching combined with atomic force microscopy. Single neutral excitons confined in these quantum rings are studied by magneto-photoluminescence. Oscillations in the exciton radiative recombination energy and in the emission intensity are observed under an applied magnetic field. Further, we demonstrate that the period of the oscillations can be tuned by a gate potential that modifies the exciton confinement. The experimental results, combined with calculations, indicate that the exciton Aharonov-Bohm effect may account for the observed effects. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000290692200005 |
Publication Date |
2011-04-18 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1555-130X;1555-1318; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
0.497 |
Times cited |
3 |
Open Access |
|
Notes |
; We acknowledge L. P. Kouwenhoven and Z. G. Wang for support, C. C. Bof Bufon, C. Deneke, V. Fomin, A. Govorov, S. Kiravittaya, and Wen-Hao Chang for their help and discussions. We are grateful for the financial support of NWO (VIDI), the CAS-MPG programm, the DFG (FOR730), BMBF (No. 01BM459), NSFC China (60625402), and Flemish Science Foundation (FWO-V1). ; |
Approved |
Most recent IF: 0.497; 2011 IF: 0.556 |
Call Number |
UA @ lucian @ c:irua:90187 |
Serial |
3025 |
Permanent link to this record |
|
|
|
Author |
Smeulders, G.; van Oers, C.; Van Havenbergh, K.; Houthoofd, K.; Mertens, M.; Martens, J.A.; Bals, S.; Maes, B.U.W.; Meynen, V.; Cool, P. |
Title |
Smart heating profiles for the synthesis of benzene bridged periodic mesoporous organosilicas |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Chemical engineering journal |
Abbreviated Journal |
Chem Eng J |
Volume |
175 |
Issue |
|
Pages |
585-591 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY) |
Abstract |
In this study the effects of the heating rate and heating time on the formation of crystal-like benzene bridged periodic mesoporous organosilicas (PMOs) are investigated. The time needed to heat up an autoclave during the hydrothermal treatment has shown to be crucial in the synthesis of PMOs, while the total duration of heating gave rise to only minor differences. By choosing a smart heating profile, superior PMO materials can be obtained in a short time. Different heating profiles in a range from one minute to one hour are adopted by microwave equipment and compared with conventional heating methods. The heating rate has a large influence on the porosity characteristics and the uniformity of the obtained particles. Moreover, two new alternative synthetic strategies to adopt the smart heating profile are presented, in order to give some possible solutions for the expensive microwave equipment. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Lausanne |
Editor |
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Language |
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Wos |
000297875900069 |
Publication Date |
2011-10-07 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1385-8947; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.216 |
Times cited |
7 |
Open Access |
|
Notes |
Fwo; Goa-Bof |
Approved |
Most recent IF: 6.216; 2011 IF: 3.461 |
Call Number |
UA @ lucian @ c:irua:93630 |
Serial |
3044 |
Permanent link to this record |
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Author |
Hadermann, J.; Abakumov, A.M.; Turner, S.; Hafideddine, Z.; Khasanova, N.R.; Antipov, E.V.; Van Tendeloo, G. |
Title |
Solving the structure of Li ion battery materials with precession electron diffraction : application to Li2CoPo4F |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
23 |
Issue |
15 |
Pages |
3540-3545 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The crystal structure of the Li2CoPO4F high-voltage cathode for Li ion rechargeable batteries has been completely solved from precession electron diffraction (PED) data, including the location of the Li atoms. The crystal structure consists of infinite chains of CoO4F2 octahedra sharing common edges and linked into a 3D framework by PO4 tetrahedra. The chains and phosphate anions together delimit tunnels filled with the Li atoms. This investigation demonstrates that PED can be successfully applied for obtaining structural information on a variety of Li-containing electrode materials even from single micrometer-sized crystallites. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000293357100019 |
Publication Date |
2011-07-11 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
46 |
Open Access |
|
Notes |
Fwo; Bof |
Approved |
Most recent IF: 9.466; 2011 IF: 7.286 |
Call Number |
UA @ lucian @ c:irua:90357 |
Serial |
3053 |
Permanent link to this record |
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|
|
Author |
Wu, Z.; Peeters, F.M.; Chang, K. |
Title |
Spin and momentum filtering of electrons on the surface of a topological insulator |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
Volume |
98 |
Issue |
16 |
Pages |
162101,1-162101,3 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We investigate theoretically the transport properties of Dirac fermions on the surface of a three-dimensional topological insulator. Dirac electrons can be totally reflected in front of a magnetic/electric p-n junction. For a p-n-p structure, multiple total internal reflections at the interfaces result in the bound states in the channel, which behaves like an electronic waveguide. This p-n-p like structure exhibits spin and momentum filtering features and could be used as a spin and/or charge diode. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
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Wos |
000289842700032 |
Publication Date |
2011-04-18 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.411 |
Times cited |
33 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 3.411; 2011 IF: 3.844 |
Call Number |
UA @ lucian @ c:irua:89971 |
Serial |
3076 |
Permanent link to this record |
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Author |
Glazov, M.M.; Semina, M.A.; Badalyan, S.M.; Vignale, G. |
Title |
Spin-current generation from Coulomb-Rashba interaction in semiconductor bilayers |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
3 |
Pages |
033305-033305,4 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Electrons in double-layer semiconductor heterostructures experience a special type of spin-orbit interaction that arises in each layer from the perpendicular component of the Coulomb electric field created by electron-density fluctuations in the other layer. We show that this interaction, acting in combination with the usual spin-orbit interaction, can generate a spin current in one layer when a charge current is driven in the other. This effect is distinct symmetrywise from the spin-Hall drag. The spin current is not, in general, perpendicular to the drive current. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000293129200001 |
Publication Date |
2011-07-26 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
5 |
Open Access |
|
Notes |
; M.M.G. and M. A. S. are grateful to RFBR, EU projects Spinoptronics and POLAPHEN, and the “Dynasty” Foundation-ICFPM for financial support. S. M. B. acknowledges support from EU Grant No. PIIF-GA-2009-235394, the DFG SFB 689, and the Belgium Science Policy (IAP). G. V. acknowledges support from NSF Grant No. DMR-0705460. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:91740 |
Serial |
3081 |
Permanent link to this record |
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Author |
Abakumov, A.M.; Tsirlin, A.A.; Perez-Mato, J.M.; Petřiček, V.; Rosner, H.; Yang, T.; Greenblatt, M. |
Title |
Spiral ground state against ferroelectricity in the frustrated magnet BiMnFe2O6 |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
83 |
Issue |
21 |
Pages |
214402-214402,10 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The spiral magnetic structure and underlying spin lattice of BiMnFe2O6 are investigated by low-temperature neutron powder diffraction and density functional theory band structure calculations. In spite of the random distribution of the Mn3+ and Fe3+ cations, this centrosymmetric compound undergoes a transition into an incommensurate antiferromagnetically ordered state below TN≃220 K. The magnetic structure is characterized by the propagation vector k=[0,β,0] with β≃0.14 and the P221211′(0β0)0s0s magnetic superspace symmetry. It comprises antiferromagnetic helixes propagating along the b axis. The magnetic moments lie in the ac plane and rotate about π(1+β)≃204.8-deg angle between the adjacent magnetic atoms along b. The spiral magnetic structure arises from the peculiar frustrated arrangement of exchange couplings in the ab plane. The antiferromagnetic coupling along the c axis cancels the possible electric polarization and prevents ferroelectricity in BiMnFe2O6. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000291197400001 |
Publication Date |
2011-06-03 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
12 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:90080 |
Serial |
3107 |
Permanent link to this record |
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Author |
Fang, C.M.; van Huis, M.A.; Zandbergen, H.W. |
Title |
Stability and structures of the \epsilon-phases of iron nitrides and iron carbides from first principles |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Scripta materialia |
Abbreviated Journal |
Scripta Mater |
Volume |
64 |
Issue |
3 |
Pages |
296-299 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
First-principles calculations were performed for the ε-phases and other iron carbides/nitrides with hexagonal close-packed Fe sublattices. Although these nitrides/carbides have similar crystal structures, they exhibit different chemical and physical properties. Relative to α-Fe, graphite and N2, all the ε-type nitrides are stable, while all the carbides are metastable. The lattice parameters of the ε-iron nitrides vary differently from those of the ε-carbides, as a function of the concentration of X (Xdouble bond; length as m-dashN, C). The structural relationships of ε-Fe2X with η-Fe2X and ζ-Fe2X are discussed. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
|
Language |
|
Wos |
000285323300022 |
Publication Date |
2010-09-02 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1359-6462; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.747 |
Times cited |
29 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.747; 2011 IF: 2.699 |
Call Number |
UA @ lucian @ c:irua:86974 |
Serial |
3120 |
Permanent link to this record |
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Author |
Canioni, R.; Roch-Marchal, C.; Sécheresse, F.; Horcajada, P.; Serre, C.; Hardi-Dan, M.; Férey, G.; Grenèche, J.-M.; Lefebvre, F.; Chang, J.-S.; Hwang, Y.-K.; Lebedev, O.; Turner, S.; Van Tendeloo, G. |
Title |
Stable polyoxometalate insertion within the mesoporous metal organic framework MIL-100(Fe) |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of materials chemistry |
Abbreviated Journal |
J Mater Chem |
Volume |
21 |
Issue |
4 |
Pages |
1226-1233 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Successful encapsulation of polyoxometalate (POM) within the framework of a mesoporous iron trimesate MIL-100(Fe) sample has been achieved by direct hydrothermal synthesis in the absence of fluorine. XRPD, 31P MAS NMR, IR, EELS, TEM and 57Fe Mössbauer spectrometry corroborate the insertion of POM within the cavities of the MOF. The experimental Mo/Fe ratio is 0.95, in agreement with the maximum theoretical amount of POM loaded within the pores of MIL-100(Fe), based on steric hindrance considerations. The POM-MIL-100(Fe) sample exhibits a pore volume of 0.373 cm3 g−1 and a BET surface area close to 1000 m2 g−1, indicating that small gas molecules can easily diffuse inside the cavities despite the presence of heavy phosphomolybdates. These latter contribute to the decrease in the overall surface area, due to the increase in molar weight, by 65%. Moreover, the resulting Keggin containing MIL-100(Fe) solid is stable in aqueous solution with no POM leaching even after more than 2 months. In addition, no exchange of the Keggin anions by tetrabutylammonium perchlorate in organic media has been observed. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Cambridge |
Editor |
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Language |
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Wos |
000286110400042 |
Publication Date |
2010-11-25 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
|
ISSN |
0959-9428;1364-5501; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
158 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:88642 |
Serial |
3145 |
Permanent link to this record |
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Author |
Scalise, E.; Houssa, M.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A. |
Title |
Structural and vibrational properties of amorphous GeO2 from first-principles |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
Volume |
98 |
Issue |
20 |
Pages |
202110,1-202110,3 |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
The structural and vibrational properties of amorphous germanium oxide (a-GeO<sub>2</sub>) are investigated using first-principles calculations based on density functional theory. We first generate an a-GeO<sub>2</sub> structure by first-principles molecular dynamics and analyze its structural properties. The vibrational spectra is then calculated within a density-functional approach. Both static and dynamic properties are in good agreement with experimental data. We next generate defects in our structure (oxygen vacancies with several density and charge states) and consider the most stable atomic configurations, focusing on the vibrational features of threefold coordinated O and divalent Ge centers. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000290812100038 |
Publication Date |
2011-05-20 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.411 |
Times cited |
226 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.411; 2011 IF: 3.844 |
Call Number |
UA @ lucian @ c:irua:90222 |
Serial |
3202 |
Permanent link to this record |
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Author |
Rusakov, D.; Abakumov, A.M.; Yamaura, K.; Belik, A.A.; Van Tendeloo, G.; Takayama-Muromachi, E. |
Title |
Structural evolution of the BiFeO3-LaFeO3 system |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
23 |
Issue |
2 |
Pages |
285-292 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The (1 − x)BiFeO3−xLaFeO3 system has been investigated and characterized by room-temperature and high-temperature laboratory and synchrotron powder X-ray diffraction, electron diffraction, high-resolution transmission electron microscopy, differential scanning calorimetry, and magnetization measurements. At room temperature, the ferroelectric R3c phase is observed for 0.0 ≤ x ≤ 0.10. The PbZrO3-related √2ap × 2√2ap × 4ap superstructure (where ap is the parameter of the cubic perovskite subcell) is observed for Bi0.82La0.18FeO3, while an incommensurately modulated phase is formed for 0.19 ≤ x ≤ 0.30 with the √2ap × 2ap × √2ap basic unit cell. The GdFeO3-type phase with space group Pnma (√2ap × 2ap × √2ap) is stable at 0.50 ≤ x ≤ 1. Bi0.82La0.18FeO3 has no detectable homogeneity range (space group Pnam, a = 5.6004(1) Å, b = 11.2493(3) Å, c = 15.6179(3) Å). The incommensurately modulated Bi0.75La0.25FeO3 structure was solved from synchrotron X-ray powder diffraction data (Imma(00γ)s00 superspace group, a = 5.5956(1) Å, b = 7.8171(1) Å, c = 5.62055(8) Å, q = 0.4855(4)c*, RP = 0.023, RwP = 0.033). In this structure, cooperative displacements of the Bi and O atoms occur, which order within the (AO) (where A = Bi, La) layers, resulting in an antipolar structure. Local fluctuations of the intralayer antipolar ordering are compensated by an interaction with the neighboring (AO) layers. A coupling of the antipolar displacements with the cooperative tilting distortion of the perovskite octahedral framework is proposed as the origin of the incommensurability. All the phases transform to the GdFeO3-type structure at high temperatures. Bi0.82La0.18FeO3 shows an intermediate PbZrO3-type phase with √2ap × 2√2ap × 2ap (space group Pbam; a = 5.6154(2) Å, b = 11.2710(4) Å, and c = 7.8248(2) Å at 570 K). The compounds in the compositional range of 0.18 ≤ x ≤ 0.95 are canted antiferromagnets. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000286160800021 |
Publication Date |
2010-12-23 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
133 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 9.466; 2011 IF: 7.286 |
Call Number |
UA @ lucian @ c:irua:88650 |
Serial |
3236 |
Permanent link to this record |
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Author |
Dzhurakhalov, A.A.; Peeters, F.M. |
Title |
Structure and energetics of hydrogen chemisorbed on a single graphene layer to produce graphane |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
Volume |
49 |
Issue |
10 |
Pages |
3258-3266 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Integrated Molecular Plant Physiology Research (IMPRES) |
Abstract |
Chemisorption of hydrogen on graphene is studied using atomistic simulations with the second generation of reactive empirical bond order Brenner inter-atomic potential. The lowest energy adsorption sites and the most important metastable sites are determined. The H concentration is varied from a single H atom, to clusters of H atoms up to full coverage. We found that when two or more H atoms are present, the most stable configurations of H chemisorption on a single graphene layer are ortho hydrogen pairs adsorbed on one side or on both sides of the graphene sheet. The latter has the highest hydrogen binding energy. The next stable configuration is the orthopara pair combination, and then para hydrogen pairs. The structural changes of graphene caused by chemisorbed hydrogen are discussed and are compared with existing experimental data and other theoretical calculations. The obtained results will be useful for nanoengineering of graphene by hydrogenation and for hydrogen storage. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000291959300014 |
Publication Date |
2011-04-15 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0008-6223; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.337 |
Times cited |
46 |
Open Access |
|
Notes |
; A.D. thanks M.W. Zhao for a useful correspondence. This work was supported by the Belgian Science Policy (IAP) and the Flemish Science Foundation (FWO-VI). ; |
Approved |
Most recent IF: 6.337; 2011 IF: 5.378 |
Call Number |
UA @ lucian @ c:irua:90877 |
Serial |
3275 |
Permanent link to this record |
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Author |
Vansweevelt, R.; Mortet, V.; D' Haen, J.; Ruttens, bart; van Haesendonck, C.; Partoens, B.; Peeters, F.M.; Wagner, P. |
Title |
Study on the giant positive magnetoresistance and Hall effect in ultrathin graphite flakes |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physica status solidi : A : applications and materials science |
Abbreviated Journal |
Phys Status Solidi A |
Volume |
208 |
Issue |
6 |
Pages |
1252-1258 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
In this paper, we report on the electronic transport properties of mesoscopic, ultrathin graphite flakes with a thickness corresponding to a stack of 150 graphene layers. The graphite flakes show an unexpectedly strong positive magnetoresistance (PMR) already at room temperature, which scales in good approximation with the square of the magnetic field. Furthermore, we show that the resistivity is unaffected by magnetic fields oriented in plane with the graphene layers. Hall effect measurements indicate that the charge carriers are p-type and their concentration increases with increasing temperature while the mobility is decreasing. The Hall voltage is non-linear in higher magnetic fields. Possible origins of the observed effects are discussed. Ball and stick model of the two topmost carbon layers of the hexagonal graphite structure. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
|
Editor |
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Language |
|
Wos |
000292945800008 |
Publication Date |
2011-02-24 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1862-6300; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.775 |
Times cited |
8 |
Open Access |
|
Notes |
; The authors gratefully acknowledge the support by FWO – Research Foundation Flanders (project G.0159.07 “Structural and electronic properties of biologically modified, graphene-based layers”), by the Federal Belgian Interuniversity Attraction Poles Programme BELSPO (project TAP VI P6/42 “Quantum effects in clusters and nanowires”) and by the Methusalem network “NANO – Antwerp-Hasselt,” funded by the Flemish Community. Technical assistance by Stoffel D. Janssens (magnet calibration and software development), Dr. Hong Yin (AFM-based thickness studies), Dr. Ronald Thoelen (data analysis), and Prof. Hans-Gerd Boyen (XPS spectroscopy) is greatly appreciated. ; |
Approved |
Most recent IF: 1.775; 2011 IF: 1.463 |
Call Number |
UA @ lucian @ c:irua:91941 |
Serial |
3343 |
Permanent link to this record |
|
|
|
Author |
Shanenko, A.A.; Croitoru, M.D.; Vagov, A.; Peeters, F.M. |
Title |
Superconducting nanowires : new type of BCS-BEC crossover driven by quantum-size effects |
Type |
P1 Proceeding |
Year |
2011 |
Publication |
|
Abbreviated Journal |
|
Volume |
|
Issue |
|
Pages |
119-127 |
Keywords |
P1 Proceeding; Condensed Matter Theory (CMT) |
Abstract |
We show that a superconducting quantum nanowire undergoes a new type of BCS-BEC crossover each time when an electron subband approaches the Fermi surface. In this case the longitudinal Cooper-pair size drops by two-three orders of magnitude down to a few nanometers. This unconventional BCS-BEC crossover is driven by quantum-size effects rather than by tuning the fermion-fermion interaction. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
Springer |
Place of Publication |
Dordrecht |
Editor |
|
Language |
|
Wos |
000289872900009 |
Publication Date |
2010-12-11 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1874-6500;1874-6535; |
ISBN |
|
Additional Links |
UA library record; WoS full record |
Impact Factor |
|
Times cited |
|
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP) and the ESF-network: INSTANS. M.D.C. acknowledges support from the Alexander von Humboldt Foundation. ; |
Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:89946 |
Serial |
3359 |
Permanent link to this record |
|
|
|
Author |
Covaci, L.; Peeters, F.M. |
Title |
Superconducting proximity effect in graphene under inhomogeneous strain |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
24 |
Pages |
241401-241401,4 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The interplay between quantum Hall states and Cooper pairs is usually hindered by the suppression of the superconducting state due to the strong magnetic fields needed to observe the quantum Hall effect. From this point of view, graphene is special since it allows the creation of strong pseudomagnetic fields due to strain. We show that in a Josephson junction made of strained graphene, Cooper pairs will diffuse into the strained region. The pair correlation function will be sublattice polarized due to the polarization of the local density of states in the zero pseudo-Landau level. We uncover two regimes: (1) one in which the cyclotron radius is larger than the junction length, in which case the supercurrent will be enhanced, and (2) the long junction regime where the supercurrent is strongly suppressed because the junction becomes an insulator. In the latter case quantized Hall states form and Andreev scattering at the normal/superconducting interface will induce edge states. Our numerical calculation has become possible due to an extension of the Chebyshev-Bogoliubovde Gennes method to computations on video cards (GPUs). |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000297766600003 |
Publication Date |
2011-12-06 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
27 |
Open Access |
|
Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Euro GRAPHENE project CONGRAN. Discussions with Andrey Chaves are gratefully acknowledged. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:93962 |
Serial |
3364 |
Permanent link to this record |
|
|
|
Author |
Esquivel, M.R.; Zelaya, E. |
Title |
Synthesis and characterisation of lanthanide-based dioxide |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Advances in applied ceramics |
Abbreviated Journal |
Adv Appl Ceram |
Volume |
110 |
Issue |
4 |
Pages |
219-224 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
In the present work, the microstructure and structure of La(0.25)Ce(0.52)Nd(0.17)Pr(0.06)(OH)(3) and La(0.25)Ce(0.52)Nd(0.17)Pr(0.06)O(2) is obtained from transmission electron microscopy and X-ray diffraction measurements. Space group P6(3)/m is assigned to the structure of La(0.25)Ce(0.52)Nd(0.17)Pr(0.06)(OH)(3). Lanthanides are assigned to Wyckoff positions 2c. Cell parameters are a=6.375(5) angstrom and c=3.753(5) angstrom. The thermal decomposition of this compound was studied by differential scanning calorimetry. The process is exothermal with an enthalpy change Delta H degrees value of -254 +/- 10 kJ mol(-1). The decomposition kinetics is complex and two global processes with E(a) values of 98 +/- 4 and 61 +/- 2 kJ mol 21 were observed. The product is a lanthanide dioxide. Space group Fm3m is assigned to the La(0.25)Ce(0.52)Nd(0.17)Pr(0.06)O(2). Lanthanides are distributed in Wyckoff positions 4a. The cell parameter is a=5.479(5) angstrom. Nanopores in the oxide surface are obtained using this method and characterised by STEM measurements. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Leeds |
Editor |
|
Language |
|
Wos |
000291206700006 |
Publication Date |
2011-05-30 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1743-6753;1743-6761; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.325 |
Times cited |
3 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 1.325; 2011 IF: 0.871 |
Call Number |
UA @ lucian @ c:irua:105588 |
Serial |
3410 |
Permanent link to this record |
|
|
|
Author |
Yang, T.; Perkisas, T.; Hadermann, J.; Croft, M.; Ignatov, A.; Van Tendeloo, G.; Greenblatt, M. |
Title |
Synthesis and structure determination of ferromagnetic semiconductors LaAMnSnO6(A = Sr, Ba) |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of materials chemistry |
Abbreviated Journal |
J Mater Chem |
Volume |
21 |
Issue |
1 |
Pages |
199-205 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
LaAMnSnO(6) (A = Sr, Ba) have been synthesized by high temperature solid-state reactions under dynamic 1% H(2)/Ar flow. Rietveld refinements on room temperature powder X-ray diffraction data indicate that LaSrMnSnO(6) crystallizes in the GdFeO(3)-structure, with space group Pnma and, combined with transmission electron microscopy, LaBaMnSnO(6) in Imma. Both space groups are common in disordered double-perovskites. The Mn(3+) and Sn(4+) ions whose valence states were confirmed by X-ray absorption spectroscopy, are completely disordered over the B-sites and the BO(6) octahedra are slightly distorted. LaAMnSnO(6) are ferromagnetic semiconductors with a T(C) = 83 K for the Sr- and 66 K for the Ba-compound. The title compounds, together with the previously reported LaCaMnSnO(6) provide an interesting example of progression from Pnma to Imma as the tolerance factor increases. An analysis of the relationship between space group and tolerance factor for the series LaAMnMO(6) (A = Ca, Sr, Ba; M = Sn, Ru) provides a better understanding of the symmetry determination for double perovskites. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Cambridge |
Editor |
|
Language |
|
Wos |
000285067300025 |
Publication Date |
2010-10-26 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0959-9428;1364-5501; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
3 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:95527 |
Serial |
3440 |
Permanent link to this record |
|
|
|
Author |
Novitskaya, M.; Makhnach, L.; Ivashkevich, L.; Pankov, V.; Klein, H.; Regeau, A.; David, J.; Gemmi, M.; Hadermann, J.; Strobel, P. |
Title |
Synthesis, crystal structure and physico-chemical properties of the new quaternary oxide Sr5BiNi2O9.6 |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of solid state chemistry |
Abbreviated Journal |
J Solid State Chem |
Volume |
184 |
Issue |
12 |
Pages |
3262-3268 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
A new black quaternary oxide Sr5BiNi2O9.6 was synthesized by solid state reaction at 1200 °C. Its structure was solved by electron crystallography and X-ray powder refinement, yielding a tetragonal structure with space group I4/mmm, a=5.3637 (2) Å, c=17.5541(5) Å, Z=4. The structure can be described as a stacking of (Bi,Sr)O rocksalt slabs and SrNiO3−δ perovskite slabs. The initial nickel valence is close to +3.1. Thermogravimetry and high-temperature oxygen coulometry showed that this compound has variable oxygen content as a function of temperature and oxygen pressure, and ultimately decomposes when heated in low oxygen pressure above 800 °C. It is a metallic conductor with n-type conduction. Its thermoelectric power was determined and found to be −20 and −38 μV/K at 300 and 650 °C, respectively. Magnetic measurements confirm the nickel valence close to +3 and show evidence of magnetic ordering at 20 K. |
Address |
|
Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
London |
Editor |
|
Language |
|
Wos |
000297662500021 |
Publication Date |
2011-10-20 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0022-4596; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.299 |
Times cited |
4 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.299; 2011 IF: 2.159 |
Call Number |
UA @ lucian @ c:irua:94016 |
Serial |
3451 |
Permanent link to this record |
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|
|
Author |
Katti, G.; Stucchi, M.; Velenis, D.; Sorée, B.; de Meyer, K.; Dehaene, W. |
Title |
Temperature-dependent modeling and characterization of through-silicon via capacitance |
Type |
A1 Journal article |
Year |
2011 |
Publication |
IEEE electron device letters |
Abbreviated Journal |
Ieee Electr Device L |
Volume |
32 |
Issue |
4 |
Pages |
563-565 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
A semianalytical model of the through-silicon via (TSV) capacitance for elevated operating temperatures is derived and verified with electrical measurements. The effect of temperature on the increase in TSV capacitance over different technology parameters is explored, and it is shown that higher oxide thickness reduces the impact of temperature rise on TSV capacitance, while with low doped substrates, which are instrumental for reducing the TSV capacitance, the sensitivity of TSV capacitance to temperature is large and cannot be ignored. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000288664800045 |
Publication Date |
2011-03-04 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0741-3106;1558-0563; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.048 |
Times cited |
27 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 3.048; 2011 IF: 2.849 |
Call Number |
UA @ lucian @ c:irua:89402 |
Serial |
3498 |
Permanent link to this record |
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|
|
Author |
Hao, Y.L.; Djotyan, A.P.; Avetisyan, A.A.; Peeters, F.M. |
Title |
D- shallow donor near a semiconductor-metal and a semiconductor-dielectric interface |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
Volume |
23 |
Issue |
11 |
Pages |
115303,1-115313,9 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The ground state energy and the extent of the wavefunction of a negatively charged donor (D − ) located near a semiconductormetal or a semiconductordielectric interface are obtained. We apply the effective mass approximation and use a variational two-electron wavefunction that takes into account the influence of all image charges that arise due to the presence of the interface, as well as the correlation between the two electrons bound to the donor. For a semiconductormetal interface, the D − binding energy is enhanced for donor positions d > 1.5aB (aB is the effective Bohr radius) due to the additional attraction of the electrons with their images. When the donor approaches the interface (i.e. d < 1.5aB) the D − binding energy drops and eventually it becomes unbound. For a semiconductordielectric (or a semiconductorvacuum) interface the D − binding energy is reduced for any donor position as compared to the bulk case and the system becomes rapidly unbound when the donor approaches the interface. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
London |
Editor |
|
Language |
|
Wos |
000287969200013 |
Publication Date |
2011-03-04 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0953-8984;1361-648X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.649 |
Times cited |
5 |
Open Access |
|
Notes |
; This work was supported by the Belgian Science Policy (IAP) and the Brazilian Science Foundation CNPq. One of us (AAA) was supported by a fellowship from the Belgian Federal Science Policy Office (IAP). ; |
Approved |
Most recent IF: 2.649; 2011 IF: 2.546 |
Call Number |
UA @ lucian @ c:irua:88828 |
Serial |
3528 |
Permanent link to this record |
|
|
|
Author |
Paul, M.; Kufer, D.; Müller, A.; Brück, S.; Goering, E.; Kamp, M.; Verbeeck, J.; Tian, H.; Van Tendeloo, G.; Ingle, N.J.C.; Sing, M.; Claessen, R. |
Title |
Fe3O4/ZnO : a high-quality magnetic oxide-semiconductor heterostructure by reactive deposition |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
Volume |
98 |
Issue |
1 |
Pages |
012512,1-012512,3 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We demonstrate the epitaxial growth of Fe<sub>3</sub>O<sub>4</sub> films on ZnO by a simple reactive deposition procedure using molecular oxygen as an oxidizing agent. X-ray photoelectron spectroscopy results evidence that the iron-oxide surface is nearly stoichiometric magnetite. X-ray diffraction results indicate monocrystalline epitaxy and almost complete structural relaxation. Scanning transmission electron micrographs reveal that the microstructure consists of domains which are separated by antiphase boundaries or twin boundaries. The magnetite films show rather slow magnetization behavior in comparison with bulk crystals probably due to reduced magnetization at antiphase boundaries in small applied fields. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000286009800055 |
Publication Date |
2011-01-07 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.411 |
Times cited |
27 |
Open Access |
|
Notes |
The authors acknowledge financial support by DFG through Forschergruppe FOR 1162. |
Approved |
Most recent IF: 3.411; 2011 IF: 3.844 |
Call Number |
UA @ lucian @ c:irua:88653 |
Serial |
3532 |
Permanent link to this record |
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|
Author |
Stankovski, M.; Antonius, G.; Waroquiers, D.; Miglio, A.; Dixit, H.; Sankaran, K.; Giantomassi, M.; Gonze, X.; Côté, M.; Rignanese, G.-M. |
Title |
G0W0 band gap of ZnO : effects of plasmon-pole models |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
84 |
Issue |
24 |
Pages |
241201-241201,5 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Carefully converged calculations are performed for the band gap of ZnO within many-body perturbation theory (G0W0 approximation). The results obtained using four different well-established plasmon-pole models are compared with those of explicit calculations without such models (the contour-deformation approach). This comparison shows that, surprisingly, plasmon-pole models depending on the f-sum rule gives less precise results. In particular, it confirms that the band gap of ZnO is underestimated in the G0W0 approach as compared to experiment, contrary to the recent claim of Shih et al. [ Phys. Rev. Lett. 105 146401 (2010)]. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
|
Editor |
|
Language |
|
Wos |
000297766600001 |
Publication Date |
2011-12-06 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
81 |
Open Access |
|
Notes |
; The authors would like to thank P. Zhang, S. Louie, J. Deslippe, P. Rinke, H. Jiang, C. Friedrich, and F. Bruneval for many helpful discussions. We are also very grateful to Y. Pouillon, A. Jacques, and J.-M. Beuken for their technical aid and expertise. M.C. and G.A. would like to acknowledge the support of NSERC and FQRNT. This work was supported by the Interuniversity Attraction Poles program (P6/42)-Belgian State-Belgian Science Policy, the Flemish Science Foundation (FWO-Vl) ISIMADE project, the EU's 7th Framework programme through the ETSF I3 e-Infrastructure project (Grant Agreement No. 211956), the Communaute francaise de Belgique, through the Action de Recherche Concertee 07/ 12-003 “Nanosystemes hybrides metal-organiques”, and the FNRS through FRFC Project No. 2.4.589.09.F. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
Call Number |
UA @ lucian @ c:irua:93963 |
Serial |
3533 |
Permanent link to this record |
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|
|
Author |
Korneychik, O.E.; Batuk, M.; Abakumov, A.M.; Hadermann, J.; Rozova, M.G.; Sheptyakov, D.V.; Pokholok, K.V.; Filimonov, D.S.; Antipov, E.V. |
Title |
Pb2.85Ba2.15Fe4SnO13 : a new member of the AnBnO3n-2 anion-deficient perovskite-based homologous series |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of solid state chemistry |
Abbreviated Journal |
J Solid State Chem |
Volume |
184 |
Issue |
12 |
Pages |
3150-3157 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Pb2.85Ba2.15Fe4SnO13, a new n=5 member of the anion-deficient perovskite based AnBnO3n−2 (A=Pb, Ba, B=Fe, Sn) homologous series, was synthesized by the solid state method. The crystal structure of Pb2.85Ba2.15Fe4SnO13 was investigated using a combination of neutron powder diffraction, electron diffraction, high angle annular dark field scanning transmission electron microscopy and Mössbauer spectroscopy. It crystallizes in the Ammm space group with unit cell parameters a=5.7990(1) Å, b=4.04293(7) Å and c=26.9561(5) Å. The Pb2.85Ba2.15Fe4SnO13 structure consists of quasi two-dimensional perovskite blocks separated by 1/2[110](1̄01)p crystallographic shear (CS) planes. The corner-sharing FeO6 octahedra at the CS planes are transformed into edge-sharing FeO5 distorted tetragonal pyramids. The octahedral positions in the perovskite blocks between the CS planes are jointly taken up by Fe and Sn, with a preference of Sn towards the position at the center of the perovskite block. The chains of FeO5 pyramids and (Fe,Sn)O6 octahedra of the perovskite blocks delimit six-sided tunnels at the CS planes occupied by double chains of Pb atoms. The compound is antiferromagnetically ordered below TN=368±15 K. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
London |
Editor |
|
Language |
|
Wos |
000297662500003 |
Publication Date |
2011-09-30 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0022-4596; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.299 |
Times cited |
7 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.299; 2011 IF: 2.159 |
Call Number |
UA @ lucian @ c:irua:94013 |
Serial |
3550 |
Permanent link to this record |
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|
|
Author |
Dixon, E.; Hadermann, J.; Hayward, M.A. |
Title |
The synthesis and complex anion-vacancy ordered structure of La0.33Sr0.67MnO2.42 |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of solid state chemistry |
Abbreviated Journal |
J Solid State Chem |
Volume |
184 |
Issue |
7 |
Pages |
1791-1799 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The low-temperature topotactic reduction of La0.33Sr0.67MnO3 with NaH results in the formation of La0.33Sr0.67MnO2.42. A combination of neutron powder and electron diffraction data show that La0.33Sr0.67MnO2.42 adopts a novel anion-vacancy ordered structure with a 6-layer OOTOOT' stacking sequence of the octahedral and tetrahedral layers (Pcmb, a=5.5804(1) Å, b=23.4104(7) Å, c=11.2441(3) Å). A significant concentration of anion vacancies at the anion site, which links neighbouring octahedral layers means that only 25% of the octahedral manganese coordination sites actually have 6-fold MnO6 coordination, the remainder being MnO5 square-based pyramidal sites. The chains of cooperatively twisted apex-linked MnO4 tetrahedra adopt an ordered -LRLR- arrangement within each tetrahedral layer. This is the first published example of a fully refined structure of this type which exhibits such intralayer ordering of the twisted tetrahedral chains. The rationale behind the contrasting structures of La0.33Sr0.67MnO2.42 and other previously reported reduced La1−xSrxMnO3−y phases is discussed. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
London |
Editor |
|
Language |
|
Wos |
000292718500032 |
Publication Date |
2011-05-26 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0022-4596; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.299 |
Times cited |
8 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.299; 2011 IF: 2.159 |
Call Number |
UA @ lucian @ c:irua:90885 |
Serial |
3600 |
Permanent link to this record |
|
|
|
Author |
Eckert, M.; Mortet, V.; Zhang, L.; Neyts, E.; Verbeeck, J.; Haenen, ken; Bogaerts, A. |
Title |
Theoretical investigation of grain size tuning during prolonged bias-enhanced nucleation |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
Volume |
23 |
Issue |
6 |
Pages |
1414-1423 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
In this paper, the effects of prolonged bias-enhanced nucleation (prolonged BEN) on the growth mechanisms of diamond are investigated by molecular dynamics (MD) and combined MD-Metropolis Monte Carlo (MD-MMC) simulations. First, cumulative impacts of CxHy+ and Hx+ on an a-C:H/nanodiamond composite were simulated; second, nonconsecutive impacts of the dominant ions were simulated in order to understand the observed phenomena in more detail. As stated in the existing literature, the growth of diamond structures during prolonged BEN is a process that takes place below the surface of the growing film. The investigation of the penetration behavior of CxHy+ and Hx+ species shows that the carbon-containing ions remain trapped within this amorphous phase where they dominate mechanisms like precipitation of sp3 carbon clusters. The H+ ions, however, penetrate into the crystalline phase at high bias voltages (>100 V), destroying the perfect diamond structure. The experimentally measured reduction of grain sizes at high bias voltage, reported in the literature, might thus be related to penetrating H+ ions. Furthermore, the CxHy+ ions are found to be the most efficient sputtering agents, preventing the build up of defective material. |
Address |
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Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Washington, D.C. |
Editor |
|
Language |
|
Wos |
000288291400011 |
Publication Date |
2011-02-23 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0897-4756;1520-5002; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
9.466 |
Times cited |
9 |
Open Access |
|
Notes |
Iwt; Fwo; Esteem 026019; Iap |
Approved |
Most recent IF: 9.466; 2011 IF: 7.286 |
Call Number |
UA @ lucian @ c:irua:87642 |
Serial |
3605 |
Permanent link to this record |
|
|
|
Author |
Scipioni, R.; Matsubara, M.; Ruiz, E.; Massobrio, C.; Boero, M. |
Title |
Thermal behavior of Si-doped fullerenes vs their structural stability at T = 0 K : a density functional study |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Chemical physics letters |
Abbreviated Journal |
Chem Phys Lett |
Volume |
510 |
Issue |
1/3 |
Pages |
14-17 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We establish the topological conditions underlying the thermal stability of C30Si30 clusters. Two topologies have been considered: a segregated one, where Si and C atoms lie on neighboring and yet, separated parts of the cage, and a non-segregated one, where the number of SiC bonds is maximized. The segregated network is energetically favored against the non-segregated one, both structures being fully relaxed at T = 0 K. Conversely, the non-segregated structure is the only one stable at finite temperatures, regardless of the nature of the local states (d or p) included in the KleynmanBylander construction. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000291478400002 |
Publication Date |
2011-05-20 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0009-2614; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.815 |
Times cited |
14 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 1.815; 2011 IF: 2.337 |
Call Number |
UA @ lucian @ c:irua:90453 |
Serial |
3625 |
Permanent link to this record |
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|
|
Author |
Grodzinska, D.; Pietra, F.; van Huis, M.A.; Vanmaekelbergh, D.; de Mello Donegá, C. |
Title |
Thermally induced atomic reconstruction of PbSe/CdSe core/shell quantum dots into PbSe/CdSe bi-hemisphere hetero-nanocrystals |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Journal of materials chemistry |
Abbreviated Journal |
J Mater Chem |
Volume |
21 |
Issue |
31 |
Pages |
11556-11565 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
The properties of hetero-nanocrystals (HNCs) depend strongly on the mutual arrangement of the nanoscale components. In this work we have investigated the structural and morphological evolution of colloidal PbSe/CdSe core/shell quantum dots upon annealing under vacuum. Prior to annealing the PbSe core has an approximately octahedral morphology with eight {111} facets, and the CdSe shell has zinc-blende crystal structure. Thermal annealing under vacuum at temperatures between 150 °C and 200 °C induces a structural and morphological reconstruction of the HNCs whereby the PbSe core and the CdSe shell are reorganized into two hemispheres joined by a common {111} Se plane. This thermally induced reconstruction leads to considerable changes in the optical properties of the colloidal PbSe/CdSe HNCs. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Cambridge |
Editor |
|
Language |
|
Wos |
000293190200018 |
Publication Date |
2011-04-21 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0959-9428;1364-5501; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
44 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:91945 |
Serial |
3632 |
Permanent link to this record |
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|
|
Author |
Bals, S.; Casavola, M.; van Huis, M.A.; Van Aert, S.; Batenburg, K.J.; Van Tendeloo, G.; Vanmaekelbergh, D. |
Title |
Three-dimensional atomic imaging of colloidal core-shell nanocrystals |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Nano letters |
Abbreviated Journal |
Nano Lett |
Volume |
11 |
Issue |
8 |
Pages |
3420-3424 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
Colloidal coreshell semiconductor nanocrystals form an important class of optoelectronic materials, in which the exciton wave functions can be tailored by the atomic configuration of the core, the interfacial layers, and the shell. Here, we provide a trustful 3D characterization at the atomic scale of a free-standing PbSe(core)CdSe(shell) nanocrystal by combining electron microscopy and discrete tomography. Our results yield unique insights for understanding the process of cation exchange, which is widely employed in the synthesis of coreshell nanocrystals. The study that we present is generally applicable to the broad range of colloidal heteronanocrystals that currently emerge as a new class of materials with technological importance. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Washington |
Editor |
|
Language |
|
Wos |
000293665600062 |
Publication Date |
2011-07-25 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1530-6984;1530-6992; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
12.712 |
Times cited |
121 |
Open Access |
|
Notes |
Esteem 026019; Fwo |
Approved |
Most recent IF: 12.712; 2011 IF: 13.198 |
Call Number |
UA @ lucian @ c:irua:91263 |
Serial |
3643 |
Permanent link to this record |
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|
|
Author |
Van Aert, S.; Batenburg, K.J.; Rossell, M.D.; Erni, R.; Van Tendeloo, G. |
Title |
Three-dimensional atomic imaging of crystalline nanoparticles |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Nature |
Abbreviated Journal |
Nature |
Volume |
470 |
Issue |
7334 |
Pages |
374-377 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab |
Abstract |
Determining the three-dimensional (3D) arrangement of atoms in crystalline nanoparticles is important for nanometre-scale device engineering and also for applications involving nanoparticles, such as optoelectronics or catalysis. A nanoparticles physical and chemical properties are controlled by its exact 3D morphology, structure and composition1. Electron tomography enables the recovery of the shape of a nanoparticle from a series of projection images2, 3, 4. Although atomic-resolution electron microscopy has been feasible for nearly four decades, neither electron tomography nor any other experimental technique has yet demonstrated atomic resolution in three dimensions. Here we report the 3D reconstruction of a complex crystalline nanoparticle at atomic resolution. To achieve this, we combined aberration-corrected scanning transmission electron microscopy5, 6, 7, statistical parameter estimation theory8, 9 and discrete tomography10, 11. Unlike conventional electron tomography, only two images of the targeta silver nanoparticle embedded in an aluminium matrixare sufficient for the reconstruction when combined with available knowledge about the particles crystallographic structure. Additional projections confirm the reliability of the result. The results we present help close the gap between the atomic resolution achievable in two-dimensional electron micrographs and the coarser resolution that has hitherto been obtained by conventional electron tomography. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
London |
Editor |
|
Language |
|
Wos |
000287409100037 |
Publication Date |
2011-02-02 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0028-0836;1476-4687; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
40.137 |
Times cited |
341 |
Open Access |
|
Notes |
Esteem 026019 |
Approved |
Most recent IF: 40.137; 2011 IF: 36.280 |
Call Number |
UA @ lucian @ c:irua:86745 |
Serial |
3644 |
Permanent link to this record |
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|
|
Author |
Nasirpouri, F.; Engbarth, M.A.; Bending, S.J.; Peter, L.M.; Knittel, A.; Fangohr, H.; Milošević, M.V. |
Title |
Three-dimensional ferromagnetic architectures with multiple metastable states |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
Volume |
98 |
Issue |
22 |
Pages |
222506,1-222506,3 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We demonstrate controllable dual-bath electrodeposition of nickel on architecture-tunable three-dimensional (3D) silver microcrystals. Magnetic hysteresis loops of individual highly faceted Ag-Ni core-shell elements reveal magnetization reversal that comprises multiple sharp steps corresponding to different stable magnetic states. Finite-element micromagnetic simulations on smaller systems show several jumps during magnetization reversal which correspond to transitions between different magnetic vortex states. Structures of this type could be realizations of an advanced magnetic data storage architecture whereby each element represents one multibit, storing a combination of several conventional bits depending on the overall number of possible magnetic states associated with the 3D core-shell shape. |
Address |
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Corporate Author |
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Thesis |
|
Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000291405700044 |
Publication Date |
2011-06-03 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0003-6951; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.411 |
Times cited |
8 |
Open Access |
|
Notes |
; This work was supported by EPSRC in the U.K. under Grant Nos. EP/E039944/1 and EP/E040063/1, DYNAMAG project (EU FP7/2007-2013 Grant No. 233552), and FWO-Vlaanderen. ; |
Approved |
Most recent IF: 3.411; 2011 IF: 3.844 |
Call Number |
UA @ lucian @ c:irua:90008 |
Serial |
3652 |
Permanent link to this record |
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|
|
Author |
Zarenia, M.; Pereira, J.M.; Peeters, F.M.; Farias, G. de A. |
Title |
Topological confinement in an antisymmetric potential in bilayer graphene in the presence of a magnetic field |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Nanoscale research letters |
Abbreviated Journal |
Nanoscale Res Lett |
Volume |
6 |
Issue |
|
Pages |
452,1-452,10 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We investigate the effect of an external magnetic field on the carrier states that are localized at a potential kink and a kink-antikink in bilayer graphene. These chiral states are localized at the interface between two potential regions with opposite signs. |
Address |
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Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000293299800001 |
Publication Date |
2011-07-14 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1556-276X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.833 |
Times cited |
4 |
Open Access |
|
Notes |
; This work was supported by the Brazilian agency CNPq (Pronex), the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the bilateral projects between Flanders and Brazil and FWO-CNPq. ; |
Approved |
Most recent IF: 2.833; 2011 IF: NA |
Call Number |
UA @ lucian @ c:irua:91745 |
Serial |
3674 |
Permanent link to this record |