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	Author	Adamson, P.; Hadermann, J.; Smura, C.F.; Rutt, O.J.; Hyett, G.; Free, D.G.; Clarke, S.J.
	Title	Competing magnetic structures and the evolution of copper ion/vacancy ordering with composition in the manganite oxide chalcogenides Sr₂MnO₂Cu_1.5(S_1-xSe_x)₂			Type	A1 Journal article
	Year	2012	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	24	Issue	14	Pages	2802-2816
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The series Sr2MnO2Cu1.5(S1-xSex)(2) (0 <= x <= 1) contains mixed-valent Mn ions (Mn2+/Mn3+) in MnO2 sheets which are separated by copper-deficient antifluorite-type Cu(2-delta)Ch(2) layers with delta similar to 0.5. The compounds crystallize in the structure type first described for Sr2Mn3Sb2O2 and are described in the I4/mmm space group at ambient temperatures. Below about 250 K, ordering between Cu+ ions and tetrahedral vacancies occurs which is long-range and close to complete in the sulfide-containing end member of the series Sr2MnO2Cu1.5S2 but which occurs over shorter length scales as the selenide content increases. The superstructure is an orthorhombic 2 root 2a x root 2a x c expansion in Ibam of the room temperature cell. For x > 0.3 there are no superstructure reflections evident in the X-ray or neutron diffraction patterns, and the I4/mmm description is valid for the average structure at all temperatures. However, in the pure selenide end member, Sr2MnO2Cu1.5Se2, diffuse scattering in electron diffractograms and modulation in high resolution lattice image profiles may arise from short-range Cu/vacancy order. All members of the series exhibit long-range magnetic order. In the sulfide-rich end member and in compounds with x < 0.1 in the formula Sr2MnO2Cu1.5(S1-xSex)(2), which show well developed superstructures due to long-range Cu/vacancy order, the magnetic structure has a (1/4 1/4 0) propagation vector in which ferromagnetic zigzag chains of Mn moments in the MnO2 sheets are coupled antiferromagnetically in an arrangement described as the CE-type magnetic structure and found in many mixed-valent perovskite and Ruddlesden-Popper type oxide manganites. In these cases the magnetic cell is an a x 2b x c expansion of the low temperature Ibam structural cell. For x >= 0.2 in the formula Sr2MnO2Cu1.5(S1-xSex)(2) the magnetic structure has a (0 0 0) propagation vector and is similar to the A-type structure, also commonly adopted by some perovskite-related manganites, in which the Mn moments in the MnO2 sheets are coupled ferromagnetically and long-range antiferromagnetic order results from antiferromagnetic coupling between planes. In the region of the transition between the two different structural and magnetic long-range ordering schemes (0.1 < x < 0.2) the two magnetic structures coexist in the same sample. The evolution of the competition between magnetic ordering schemes and the length scale of the structural order with composition in Sr2MnO2Cu1.5(S1-xSex)(2) suggest that the changes in magnetic and structural order are related consequences of the introduction of chemical disorder.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000306674200024	Publication Date	2012-06-20
	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	11	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 9.466; 2012 IF: 8.238
	Call Number	UA @ lucian @ c:irua:100839			Serial	435
Permanent link to this record



	Author	Khalilov, U.; Pourtois, G.; van Duin, A.C.T.; Neyts, E.C.
	Title	Self-limiting oxidation in small-diameter Si nanowires			Type	A1 Journal article
	Year	2012	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	24	Issue	11	Pages	2141-2147
	Keywords	A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
	Abstract	Recently, core shell silicon nanowires (Si-NWs) have been envisaged to be used for field-effect transistors and photovoltaic applications. In spite of the constant downsizing of such devices, the formation of ultrasmall diameter core shell Si-NWs currently remains entirely unexplored. We report here on the modeling of the formation of such core shell Si-NWs using a dry thermal oxidation of 2 nm diameter (100) Si nanowires at 300 and 1273 K, by means of reactive molecular dynamics simulations using the ReaxFF potential. Two different oxidation mechanisms are discussed, namely a self-limiting process that occurs at low temperature (300 K), resulting in a Si core I ultrathin SiO2 silica shell nanowire, and a complete oxidation process that takes place at a higher temperature (1273 K), resulting in the formation of an ultrathin SiO2 silica nanowire. The oxidation kinetics of both cases and the resulting structures are analyzed in detail. Our results demonstrate that precise control over the Si-core radius of such NWs and the SiOx (x <= 2.0) oxide shell is possible by controlling the growth temperature used during the oxidation process.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000305092600021	Publication Date	2012-05-18
	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	45	Open Access
	Notes				Approved	Most recent IF: 9.466; 2012 IF: 8.238
	Call Number	UA @ lucian @ c:irua:99079			Serial	2976
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	Author	Dendooven, J.; Goris, B.; Devloo-Casier, K.; Levrau, E.; Biermans, E.; Baklanov, M.R.; Ludwig, K.F.; van der Voort, P.; Bals, S.; Detavernier, C.
	Title	Tuning the pore size of ink-bottle mesopores by atomic layer deposition			Type	A1 Journal article
	Year	2012	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	24	Issue	11	Pages	1992-1994
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000305092600002	Publication Date	2012-05-03
	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	52	Open Access
	Notes	Fwo			Approved	Most recent IF: 9.466; 2012 IF: 8.238
	Call Number	UA @ lucian @ c:irua:99078			Serial	3760
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	Author	Turner, S.; Verbeeck, J.; Ramezanipour, F.; Greedan, J.E.; Van Tendeloo, G.; Botton, G.A.
	Title	Atomic resolution coordination mapping in Ca₂FeCoO₅ brownmillerite by spatially resolved electron energy-loss spectroscopy			Type	A1 Journal article
	Year	2012	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	24	Issue	10	Pages	1904-1909
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Using a combination of high-angle annular dark field scanning transmission electron microscopy and atomically resolved electron energy-loss spectroscopy at high energy resolution in an aberration-corrected electron microscope, we demonstrate the capability of coordination mapping in complex oxides. Brownmillerite compound Ca2FeCoO5, consisting of repetitive octahedral and tetrahedral coordination layers with Fe and Co in a fixed 3+ valency, is selected to demonstrate the principle of atomic resolution coordination mapping. Analysis of the Co-L2,3 and the Fe-L2,3 edges shows small variations in the fine structure that can be specifically attributed to Co/Fe in tetrahedral or in octahedral coordination. Using internal reference spectra, we show that the coordination of the Fe and Co atoms in the compound can be mapped at atomic resolution.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000304237500024	Publication Date	2012-04-25
	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	33	Open Access
	Notes	A.M. Abakumov is thanked for fruitful discussions. S.T. gratefully acknowledges the Fund for Scientific Research Flanders (FWO). J.E.G. and GAB. acknowledge the support of the NSERC of Canada through Discovery Grants. The Canadian Centre for Electron Microscopy is a National Facility supported by NSERC and McMaster University and was funded by the Canada Foundation for Innovation and the Ontario Government. Part of this work was supported by funding from the European Research Council under the FP7, ERC Grant N 246791 COUNTATOMS and ERC Starting Grant N 278510 VORTEX. The EMAT microscope is partially funded by the Hercules fund of the Flemish Government. ECASJO_;			Approved	Most recent IF: 9.466; 2012 IF: 8.238
	Call Number	UA @ lucian @ c:irua:98379UA @ admin @ c:irua:98379			Serial	175
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	Author	Dixon, E.; Hadermann, J.; Hayward, M.A.
	Title	Structures and magnetism of La_1-xSr_xMnO_3-(0.5+x)/2 (0.67\leq x\leq1) phases			Type	A1 Journal article
	Year	2012	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	24	Issue	8	Pages	1486-1495
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Topotactic reduction of La1-xSrxMnO3 (0.67 <= x <= 1) phases with sodium hydride yields a series of isoelectronic materials of composition La1-xSrxMnO3-(0.5+x)/2. Lanthanum rich members of the series (0.67 <= x <= 0.83) adopt anion deficient perovskite structures with a 6-layer -OTOOT'O- stacking sequence of sheets of octahedra/square-based pyramids (O) and sheets of tetrahedra (T). The strontium rich members of the series (0.83 <= x <= 1) incorporate “step defects” into this 6-layer structure in which the OTOOT'O stacking sequence is converted into either OOTOOT' or TOOT'OO at a defect plane which runs perpendicular to the [201] lattice plane. The step defects appear to provide a mechanism to relieve lattice strain and accommodate additional anion deficiency in phases with x > 0.83. Magnetization and neutron diffraction data indicate La1-xSrxMnO3-(0.5+x)/2 phases adopt antiferromagnetically ordered states at low-temperature in which the ordered arrangement of magnetic spins is incommensurate with the crystallographic lattice.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000303092300011	Publication Date	2012-03-28
	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	13	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 9.466; 2012 IF: 8.238
	Call Number	UA @ lucian @ c:irua:98253			Serial	3318
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	Author	Angelomé, P.C.; Heidari Mezerji, H.; Goris, B.; Pastoriza-Santos, I.; Pérez-Juste, J.; Bals, S.; Liz-Marzán, L.M.
	Title	Seedless synthesis of single crystalline Au nanoparticles with unusual shapes and tunable LSPR in the near-IR			Type	A1 Journal article
	Year	2012	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	24	Issue	7	Pages	1393-1399
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The plasmonic properties of metal nanoparticles have acquired great importance because of their potential applications in very diverse fields. Metal nanoparticles with localized surface plasmon resonances (LSPR) in the near-infrared (NIR, 7501300 nm) are of particular interest because tissues, blood, and water display low absorption in this spectral range, thus facilitating biomedical applications. Cetyltrimethylammonium chloride (CTAC) was used to induce the seedless formation of highly anisotropic, twisted single crystalline Au nanoparticles in a single step. The LSPR of the obtained particles can be tuned from 600 nm up to 1400 nm by simply changing the reaction temperature or the reagents concentrations. The tunability of the LSPR is closely associated with significant changes in the final particle morphology, which was studied by advanced electron microscopy techniques (3D Tomography and HAADF-STEM). Kinetic experiments were carried out to establish the growth mechanism, suggesting that slow kinetics together with the complexation of the gold salt precursor to CTAC are key factors favoring the formation of these anisotropic particles.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000302487500020	Publication Date	2012-03-16
	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	42	Open Access
	Notes	Fwo			Approved	Most recent IF: 9.466; 2012 IF: 8.238
	Call Number	UA @ lucian @ c:irua:97388			Serial	2959
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	Author	Dachraoui, W.; Hadermann, J.; Abakumov, A.M.; Tsirlin, A.A.; Batuk, D.; Glazyrin, K.; McCammon, C.; Dubrovinsky, L.; Van Tendeloo, G.
	Title	Local oxygen-vacancy ordering and twinned octahedral tilting pattern in the Bi_0.81Pb_0.19FeO_2.905 cubic perovskite			Type	A1 Journal article
	Year	2012	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	24	Issue	7	Pages	1378-1385
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The structure of Bi0.81Pb0.19FeO2.905 was investigated on different length scales using a combination of electron diffraction, high-resolution scanning transmission electron microscopy, synchrotron X-ray powder diffraction, and Mössbauer spectroscopy. In the 80300 K temperature range, the average crystal structure of Bi0.81Pb0.19FeO2.905 is a cubic Pm3̅m perovskite with a = 3.95368(3) Å at T = 300 K. The (Pb2+, Bi3+) cations and O2 anions are randomly displaced along the 110 cubic directions, indicating the steric activity of the lone pair on the Pb2+ and Bi3+ cations and a tilting distortion of the perovskite framework. The charge imbalance induced by the heterovalent Bi3+ → Pb2+ substitution is compensated by the formation of oxygen vacancies preserving the trivalent state of the Fe cations. On a short scale, oxygen vacancies are located in anion-deficient (FeO1.25) layers that are approximately 6 perovskite unit cells apart and transform every sixth layer of the FeO6 octahedra into a layer with a 1:1 mixture of corner-sharing FeO4 tetrahedra and FeO5 tetragonal pyramids. The anion-deficient layers act as twin planes for the octahedral tilting pattern of adjacent perovskite blocks. They effectively randomize the octahedral tilting and prevent the cooperative distortion of the perovskite framework. The disorder in the anion sublattice impedes cooperative interactions of the local dipoles induced by the off-center displacements of the Pb and Bi cations. Magnetic susceptibility measurements evidence the antiferromagnetic ordering in Bi0.81Pb0.19FeO2.905 at low temperatures.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000302487500018	Publication Date	2012-03-13
	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	27	Open Access
	Notes				Approved	Most recent IF: 9.466; 2012 IF: 8.238
	Call Number	UA @ lucian @ c:irua:97389			Serial	1829
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	Author	Casavola, M.; van Huis, M.A.; Bals, S.; Lambert, K.; Hens, Z.; Vanmaekelbergh, D.
	Title	Anisotropic cation exchange in PbSe/CdSe core/shell nanocrystals of different geometry			Type	A1 Journal article
	Year	2012	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	24	Issue	2	Pages	294-302
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	We present a study of Cd2+-for-Pb2+ exchange in PbSe nanocrystals (NCs) with cube, star, and rod shapes. Prolonged temperature-activated cation exchange results in PbSe/CdSe heterostructured nanocrystals (HNCs) that preserve their specific overall shape, whereas the PbSe core is strongly faceted with dominance of {111} facets. Hence, cation exchange proceeds while the Se anion lattice is preserved, and well-defined {111}/{111} PbSe/CdSe interfaces develop. Interestingly, by quenching the reaction at different stages of the cation exchange new structures have been isolated, such as coreshell nanorods, CdSe rods that contain one or two separated PbSe dots and fully zinc blende CdSe nanorods. The crystallographically anisotropic cation exchange has been characterized by a combined HRTEM/HAADF-STEM study of heterointerface evolution over reaction time and temperature. Strikingly, Pb and Cd are only intermixed at the PbSe/CdSe interface. We propose a plausible model for the cation exchange based on a layer-by-layer replacement of Pb2+ by Cd2+ enabled by a vacancy-assisted cation migration mechanism.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000299367500008	Publication Date	2011-11-17
	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	136	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 9.466; 2012 IF: 8.238
	Call Number	UA @ lucian @ c:irua:94211			Serial	124
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	Author	He, Z.; Maurice, J.-L.; Gohier, A.; Lee, C.S.; Pribat, D.; Cojocaru, C.S.
	Title	Iron catalysts for the growth of carbon nanofibers : Fe, Fe₃C or both?			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	24	Pages	5379-5387
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Iron is a widely used catalyst for the growth of carbon nanotubes (CNTs) or carbon nanofibers (CNFs) by catalytic chemical vapor deposition. However, both Fe and FeC compounds (generally, Fe3C) have been found to catalyze the growth of CNTs/CNFs, and a comparison study of their respective catalytic activities is still missing. Furthermore, the control of the crystal structure of iron-based catalysts, that is α-Fe or Fe3C, is still a challenge, which not only obscures our understanding of the growth mechanisms of CNTs/CNFs, but also complicates subsequent procedures, such as the removal of catalysts for better industrial applications. Here, we show a partial control of the phase of iron catalysts (α-Fe or Fe3C), obtained by varying the growth temperatures during the synthesis of carbon-based nanofibers/nanotubes in a plasma-enhanced chemical vapor deposition reactor. We also show that the structure of CNFs originating from Fe3C is bamboo-type, while that of CNFs originating from Fe is not. Moreover, we directly compare the growth rates of carbon-based nanofibers/nanotubes during the same experiments and find that CNFs/CNTs grown by α-Fe nanoparticles are longer than CNFs grown from Fe3C nanoparticles. The influence of the type of catalyst on the growth of CNFs is analyzed and the corresponding possible growth mechanisms, based on the different phases of the catalysts, are discussed.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000298197300014	Publication Date	2011-11-10
	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	91	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:94297			Serial	1748
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	Author	Belik, A.A.; Abakumov, A.M.; Tsirlin, A.A.; Hadermann, J.; Kim, J.; Van Tendeloo, G.; Takayama-Muromachi, E.
	Title	Article Structure and magnetic properties of BiFe_0.75Mn_0.25O₃ perovskite prepared at ambient and high pressure			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	20	Pages	4505-4514
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Solid solutions of BiFe1xMnxO3 (0.0 ≤ x ≤ 0.4) were prepared at ambient pressure and at 6 GPa. The ambient-pressure (AP) phases crystallize in space group R3c similarly to BiFeO3. The high-pressure (HP) phases crystallize in space group R3c for x = 0.05 and in space group Pnma for 0.15 ≤ x ≤ 0.4. The structure of HP-BiFe0.75Mn0.25O3 was investigated using synchrotron X-ray powder diffraction, electron diffraction, and transmission electron microscopy. HP-BiFe0.75Mn0.25O3 has a PbZrO3-related √2ap × 4ap × 2√2ap (ap is the parameter of the cubic perovskite subcell) superstructure with a = 5.60125(9) Å, b = 15.6610(2) Å, and c = 11.2515(2) Å similar to that of Bi0.82La0.18FeO3. A remarkable feature of this structure is the unconventional octahedral tilt system, with the primary ab0a tilt superimposed on pairwise clockwise and counterclockwise rotations around the b-axis according to the oioi sequence (o stands for out-of-phase tilt, and i stands for in-phase tilt). The (FeMn)O6 octahedra are distorted, with one longer metaloxygen bond (2.222.23 Å) that can be attributed to a compensation for covalent BiO bonding. Such bonding results in the localization of the lone electron pair on Bi3+ cations, as confirmed by electron localization function analysis. The relationship between HP-BiFe0.75Mn0.25O3 and antiferroelectric structures of PbZrO3 and NaNbO3 is discussed. On heating in air, HP-BiFe0.75Mn0.25O3 irreversibly transforms to AP-BiFe0.75Mn0.25O3 starting from about 600 K. Both AP and HP phases undergo an antiferromagnetic ordering at TN ≈ 485 and 520 K, respectively, and develop a weak net magnetic moment at low temperatures. Additionally, ceramic samples of AP-BiFe0.75Mn0.25O3 show a peculiar phenomenon of magnetization reversal.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000295897400015	Publication Date	2011-09-29
	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	57	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:93581			Serial	151
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	Author	Kazakov, S.M.; Abakumov, A.M.; Perz-Mato, J.M.; Ovchinnikov, A.V.; Roslova, M.V.; Boltalin, A.I.; Morozov, I.V.; Antipov, E.V.; Van Tendeloo, G.
	Title	Uniform patterns of Fe-vacancy ordering in the K_x(Fe,Co)_2-ySe₂ superconductors			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	19	Pages	4311-4316
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The Fe-vacancy ordering patterns in the superconducting KxFe2ySe2 and nonsuperconducting Kx(Fe,Co)2ySe2 samples have been investigated by electron diffraction and high angle annular dark field scanning transmission electron microscopy. The Fe-vacancy ordering occurs in the ab plane of the parent ThCr2Si2-type structure, demonstrating two types of patterns. Superstructure I retains the tetragonal symmetry and can be described with the aI = bI = as√5 (as is the unit cell parameter of the parent ThCr2Si2-type structure) supercell and I4/m space group. Superstructure II reduces the symmetry to orthorhombic with the aII = as√2, bII = 2as√2 supercell and the Ibam space group. This type of superstructure is observed for the first time in KxFe2ySe2. The Fe-vacancy ordering is inhomogeneous: the disordered areas interleave with the superstructures I and II in the same crystallite. The observed superstructures represent the compositionally dependent uniform ordering patterns of two species (the Fe atoms and vacancies) on a square lattice. More complex uniform ordered configurations, including compositional stripes, can be predicted for different chemical compositions of the KxFe2ySe2 (0 < y < 0.5) solid solutions.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000295487800005	Publication Date	2011-09-13
	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	20	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:92805			Serial	3810
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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
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		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
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	Author	Dachraoui, W.; Yang, T.; Liu, C.; Ling, G.; Hadermann, J.; Van Tendeloo, G.; Llobet, A.; Greenblatt, M.
	Title	Short-range layered A-site ordering in double perovskites NaLaBB'O₆ (B = Mn, Fe; B' = Nb, Ta)			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	9	Pages	2398-2406
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The new compounds NaLaFeTaO6, NaLaFeNbO6, NaLaMnTaO6, and NaLaMnNbO6 have been synthesized and characterized with a combination of transmission electron microscopy, X-ray powder diffraction (XRPD), neutron powder diffraction (NPD), and magnetization measurements. Through electron microscopy study, a local layered order of the A-cations has been detected without the typical occurrence of rock salt order at the B-cation site. Satellite reflections in the electron diffraction related to the local layered order are not visible on the XRPD or NPD patterns. The occurrence of local layered order is supported by pair distribution function analysis, which also reveals the presence of uncorrelated displacements of the Nb and Ta cations. The octahedra are tilted according to the system a−b+a−, and the coordinates were refined from XRPD and NPD with a disordered cation distribution in the space group Pnma. The magnetic exchange interactions in NaLaFeTaO6 and NaLaFeNbO6 are antiferromagnetic, while they are ferromagnetic in NaLaMnTaO6 and NaLaMnNbO6. Long-range magnetic ordering is not observed down to 4 K for any of the compositions.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000290063600016	Publication Date	2011-04-14
	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	14	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:89944			Serial	2996
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	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
	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
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	Author	Gélard, J.; Jehanathan, N.; Roussel, H.; Gariglio, S.; Lebedev, O.I.; Van Tendeloo, G.; Dubourdieu, C.
	Title	Off-stoichiometry effects on the crystalline and defect structure of hexagonal manganite REMnO₃ films (RE = Y, Er, Dy)			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	5	Pages	1232-1238
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The crystalline and defect structure of epitaxial hexagonal RExMnyO3 (RE = Er, Dy) films with varying cationic composition was investigated by X-ray diffraction and transmission electron microscopy. The films are composed of a strained layer at the interface with the substrate and of a relaxed layer on top of it. The critical thickness is of 10 to 25 nm. For Mn-rich films (or RE deficient), an off-stoichiometric composition maintaining the hexagonal LuMnO3-type structure is stabilized over a large range of the RE/Mn ratio (0.72−1.00), with no Mn-rich secondary phases observed. A linear dependence of the out-of-plane lattice parameter with RE/Mn is observed in this range. Out-of-phase boundary (OPB) extended defects are observed in all films and exhibit a local change in stoichiometry. Such a large solubility limit in the RE deficient region points toward the formation of vacancies on the RE site (RExMnO3−δ, with 0.72 ≤ x < 1), a phenomenon that is encountered in perovskite manganites such as LaxMnO3−δ (x < 1) and that may strongly impact the physical properties of hexagonal manganites.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000287767200022	Publication Date	2011-02-03
	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	17	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:88649			Serial	2430
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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
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000286160800021	Publication Date	2010-12-23
	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	133	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:88650			Serial	3236
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	Author	Abakumov, A.M.; Batuk, D.; Hadermann, J.; Rozova, M.G.; Sheptyakov, D.V.; Tsirlin, A.A.; Niermann, D.; Waschowski, F.; Hemberger, J.; Van Tendeloo, G.; Antipov, E.V.
	Title	Antiferroelectric (Pb,Bi)_1-xFe_1+xO_3-y perovskites modulated by crystallographic shear planes			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	2	Pages	255-265
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	We demonstrate for the first time a possibility to vary the anion content in perovskites over a wide range through a long-range-ordered arrangement of crystallographic shear (CS) planes. Anion-deficient perovskites (Pb,Bi)1−xFe1+xO3−y with incommensurately modulated structures were prepared as single phases in the compositional range from Pb0.857Bi0.094Fe1.049O2.572 to Pb0.409Bi0.567Fe1.025O2.796. Using a combination of electron diffraction and high-resolution scanning transmission electron microscopy, we constructed a superspace model describing a periodic arrangement of the CS planes. The model was verified by refinement of the Pb0.64Bi0.32Fe1.04O2.675 crystal structure from neutron powder diffraction data ((3 + 1)D S.G. X2/m(α0γ), X = [1/2,1/2,1/2,1/2], a = 3.9082(1) Å, b = 3.90333(8) Å, c = 4.0900(1) Å, β = 91.936(2)°, q = 0.05013(4)a* + 0.09170(3)c* at T = 700 K, RP = 0.036, RwP = 0.048). The (Pb,Bi)1−xFe1+xO3−y structures consist of perovskite blocks separated by CS planes confined to nearly the (509)p perovskite plane. Along the CS planes, the perovskite blocks are shifted with respect to each other over the 1/2[110]p vector that transforms the corner-sharing connectivity of the FeO6 octahedra in the perovskite framework to an edge-sharing connectivity of the FeO5 pyramids at the CS plane, thus reducing the oxygen content. Variation of the chemical composition in the (Pb,Bi)1−xFe1+xO3−y series occurs mainly because of a changing thickness of the perovskite block between the interfaces, that can be expressed through the components of the q vector as Pb6γ+2αBi1−7γ−αFe1+γ−αO3−3γ−α. The Pb, Bi, and Fe atoms are subjected to strong displacements occurring in antiparallel directions on both sides of the perovskite blocks, resulting in an antiferroelectric-type structure. This is corroborated by the temperature-, frequency-, and field-dependent complex permittivity measurements. Pb0.64Bi0.32Fe1.04O2.675 demonstrates a remarkably high resistivity >0.1 T Ω cm at room temperature and orders antiferromagnetically below TN = 608(10) K.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000286160800018	Publication Date	2010-12-23
	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	29	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:88651			Serial	136
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	Author	Hamelet, S.; Casas-Cabanas, M.; Dupont, L.; Davoisne, C.; Tarascon, J.M.; Masquelier, C.
	Title	Existence of superstructures due to large amounts of Fe vacancies in the LiFePO₄-type framework			Type	A1 Journal article
	Year	2011	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	23	Issue	1	Pages	32-38
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	LiFePO4 has been under intense scrutiny over the past decade because it stands as an attractive positive electrode material for the next generation of Li-ion batteries to power electric vehicles and hybrid electric vehicles, hence the importance of its thermal behavior. The reactivity of LiFePO4 with air at moderate temperatures is shown to be dependent on its particle size. For nanosized materials, a progressive displacement of Fe from the core structure leading to a composite made of nanosize Fe2O3 and highly defective, oxidized LixFeyPO4 compositions, among which the “ideal” formula LiFe2/3PO4. Herein we report, from both temperature-controlled X-ray diffraction and electronic diffraction microscopy, that these off-stoichiometry olivine-type compounds show a defect ordering resulting in the formation of a superstructure. Such a finding shows striking similarities with the temperature-driven oxidation of fayalite Fe2SiO4 (another olivine) to structurally defective laihunite, reported in the literature three decades ago.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000285726900007	Publication Date	2010-12-14
	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	30	Open Access
	Notes				Approved	Most recent IF: 9.466; 2011 IF: 7.286
	Call Number	UA @ lucian @ c:irua:105605			Serial	1130
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	Author	Esken, D.; Turner, S.; Lebedev, O.I.; Van Tendeloo, G.; Fischer, R.A.
	Title	Au@ZIFs: stabilization and encapsulation of cavity-size matching gold clusters inside functionalized Zeolite Imidazolate Frameworks, ZIFs			Type	A1 Journal article
	Year	2010	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	22	Issue	23	Pages	6393-6401
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The selective formation and stabilization of very small, naked metal particles inside the cavities of metal organic frameworks (MOFs) and the simultaneous realization of an even distribution of the particles throughout the crystalline MOF host matrix over a wide range of metal loading are challenging goals. MOFs reveal high specific surface areas, tunable pore sizes, and organic linkers, which are able to interact with guests. The chemically very robust zeolite imidazolate frameworks (ZIFs) are a subclass of MOFs. We chose the microporous sodalite-like ZIF-8 (Zn(MelM)(2); IM = imidazolate) and ZIF-90 (Zn(ICA)(2); ICA = imidazolate-2-carboxyaldehyde) as host matrices to influence the dispersion of imbedded gold nanoparticles (Au NPs). The metal loading was achieved via gas phase infiltration of [Au(CO)Cl] followed by a thermal hydrogenation step to form the Au NPs. Low-dose high-resolution transmission electron microscopy ((HR)TEM) and electron tomography reveal a homogeneous distribution of Au NPs throughout the ZIF matrix. The functional groups of ZIF-90 direct the anchoring of intermediate Au species and stabilize drastically smaller and quite monodisperse Au NPs in contrast to the parent not functionalized ZIF-8. The particles can be very small, match the cavity size and approach defined molecular clusters of magic numbers, i.e., Au(55), independently from the level of loading. Post-synthetic oxidation of the aldehyde groups to yield alkyl esters by the adjacent, catalytically active metal NPs is presented as a new concept of encapsulating nanoparticles inside MOFs and allows multiple steps of metal loadings without decomposition of the MOF.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000284975100025	Publication Date	2010-11-12
	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	194	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 9.466; 2010 IF: 6.400
	Call Number	UA @ lucian @ c:irua:95530			Serial	208
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	Author	Efimov, K.; Xu, Q.; Feldhoff, A.
	Title	Transmission electron microscopy study of BA_0.5Sr_0.5CO_0.8Fe_0.2O_3-\delta Perovskite decomposition at intermediate temperatures			Type	A1 Journal article
	Year	2010	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	22	Issue	21	Pages	5866-5875
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The cubic perovskite Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-delta) (denoted BSCF) is the state-of-the-art ceramic membrane material used for oxygen separation technologies above 1150 K. BSCF is a mixed oxygen-ion and electron conductor (MIEC) and exhibits one of the highest oxygen permeabilities reported so far for dense oxides. Additionally, it has excellent phase stability above 1150 K. In the intermediate temperature range (750-1100 K), however, BSCF suffers from a slow decomposition of the cubic perovskite into variants with hexagonal stacking that are barriers to oxygen transport. To elucidate details of the decomposition process, both sintered BSCF ceramic and powder were annealed for 180-240 h in ambient air at temperatures below 1123 K and analyzed by different transmission electron microscopy techniques. Aside from hexagonal perovskite Ba(0.5)Sr(0.5)CoO(3-delta) , the formation of lamellar noncubic phases was observed in the quenched samples. The structure of the lamellae with the previously unknown composition Ba(1-x)Sr(x)Co(2-y)Fe(y)O(5-delta) was found to be related to the 15R hexagonal perovskite polytype. The valence and spin-state transition of cobalt leading to a considerable diminution of its ionic radius can be considered a reason for BSCF's inherent phase instability at intermediate temperatures.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000283623700010	Publication Date	2010-10-13
	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	117	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 9.466; 2010 IF: 6.400
	Call Number	UA @ lucian @ c:irua:95546			Serial	3720
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	Author	Burriel, M.; Casa-Cabanas, M.; Zapata, J.; Tan, H.; Verbeeck, J.; Solis, C.; Roqueta, J.; Skinner, S.J.; Kilner, J.A.; Van Tendeloo, G.; Santiso, J.
	Title	Influence of the microstructure on the high-temperature transport properties of GdBaCo₂O_5.5+\delta epitaxial films			Type	A1 Journal article
	Year	2010	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	22	Issue	19	Pages	5512-5520
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Epitaxial thin films of GdBaCo2O5.5+δ (GBCO) grown by pulsed laser deposition have been studied as a function of deposition conditions. The variation in film structure, domain orientation, and microstructure upon deviations in the cation composition have been correlated with the charge transport properties of the films. The epitaxial GBCO films mainly consist of single- and double-perovskite regions that are oriented in different directions depending on the deposition temperature. Additionally, cobalt depletion induces the formation of a high density of stacking defects in the films, consisting of supplementary GdO planes along the c-axis of the material. The presence of such defects progressively reduces the electrical conductivity. The films closer to the stoichiometric composition have shown p-type electronic conductivity at high pO2 with values as high as 800 S/cm at 330 °C in 1 atm O2, and with a pO2 power dependence with an exponent as low as 1/25, consistent with the behavior reported for bulk GBCO. These values place GBCO thin films as a very promising material to be applied as cathodes in intermediate temperature solid oxide fuel cells.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000282471000013	Publication Date	2010-09-20
	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	17	Open Access
	Notes	Fwo; Esteem 026019			Approved	Most recent IF: 9.466; 2010 IF: 6.400
	Call Number	UA @ lucian @ c:irua:85412UA @ admin @ c:irua:85412			Serial	1648
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	Author	Cortes-Gil, R.; Parker, D.R.; Pitcher, M.J.; Hadermann, J.; Clarke, S.J.
	Title	Indifference of superconductivity and magnetism to size-mismatched cations in the layered iron arsenides Ba_1-xNa_xFe₂As₂			Type	A1 Journal article
	Year	2010	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	22	Issue	14	Pages	4304-4311
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The evolution of the structure, magnetic ordering, and superconductivity in the series Ba(1-x)Na(x)Fe(2)As(2) is reported up to the limiting Na-rich composition with x = 0.6; the more Na-rich compositions are unstable at high temperatures with respect to competing phases. The magnetic and superconducting behaviors of the Bai,Na,Fe,As, members are similar to those of the betterinvestigated Ba(1-x)Na(x)Fe(2)As(2) analogues. This is evidently a consequence of the quantitatively similar evolution of the structure of the FeAs layers in the two series. In Ba(1-x)Na(x)Fe(2)As(2) antiferromagnetic order and an associated structural distortion are evident for x <= 0.35 and superconductivity is evident when x exceeds 0.2. For 0.4 <= x <= 0.6 bulk superconductivity is evident, and the long-range antiferromagnetically ordered state is completely suppressed. The maximum T(c) in the Ba(1-x)Na(x)Fe(2)As(2) series, as judged by the onset of diamagnetism, is 34K in Ba(0.6)Na(0.4)Fe(2)As(2). Despite the large mis-match in sizes between the two electropositive cations which separate the FeAs layers, there is no evidence for ordering of these cations on the length scale probed by electron diffraction.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000280005300027	Publication Date	2010-07-02
	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	31	Open Access
	Notes				Approved	Most recent IF: 9.466; 2010 IF: 6.400
	Call Number	UA @ lucian @ c:irua:95594			Serial	1601
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	Author	Li, Y.; Yang, X.-Y.; Tian, G.; Vantomme, A.; Yu, J.; Van Tendeloo, G.; Su, B.-L.
	Title	Chemistry of trimethyl aluminum: a spontaneous route to thermally stable 3D crystalline macroporous alumina foams with a hierarchy of pore sizes			Type	A1 Journal article
	Year	2010	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	22	Issue	10	Pages	3251-3258
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	A simple and spontaneous one-pot self-formation procedure that is easy to scale up has been developed based on the chemistry of trimethylaluminum (TMA), leading to thermally stable macroporous crystalline alumina with a very unique and unprecedented three-dimensional (3D) hierarchical pore structure consisting of well-defined wormlike mesopores. TMA is the precursor of both product and porogene (viz, two working functions within the same molecule (2 in 1)). The materials obtained have been intensively characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), N2 adsorption−desorption, and mercury porosimetry. The open cagelike macrocavities are self-constructed by mesoporous nanorods (diameter of ca. 40−70 nm), which are themselves formed by a random assembly of fibrous nanoparticles 5−6 nm in size. Optical microscopy (OM) has been used in situ to follow the synthesis procedure, which led to the proposal of the formation mechanism. Methane molecules as porogens, which were instantaneously released because of the fast hydrolysis of the chemical precursor, were the key factor in producing these 3D structures with uniform co-continuous macropores that interconnected directly with the wormlike mesopores. The important characteristic of this procedure is the concurrent formation of a multiscaled porous network. The material exhibits great thermal stability. The hierarchically mesoporous−macroporous Al2O3 obtained is quite attractive for a myriad of applications, from catalysis to biomedicine. The present work illustrates that the one-pot self-formation concept, based on the chemistry of alkyl metals, is a versatile method to design industrially valuable hierarchically porous materials.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000277635000030	Publication Date	2010-04-27
	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	38	Open Access
	Notes				Approved	Most recent IF: 9.466; 2010 IF: 6.400
	Call Number	UA @ lucian @ c:irua:82760			Serial	356
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	Author	Malo, S.; Lepoittevin, C.; Pérez, O.; Hébert, S.; Van Tendeloo, G.; Hervieu, M.
	Title	Incommensurate crystallographic shear structures and magnetic properties of the cation deficient perovskite (Sr_0.61Pb_0.18)(Fe_0.75Mn_0.25)O_2.29			Type	A1 Journal article
	Year	2010	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	22	Issue	5	Pages	1788-1797
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	The origin of the incommensurability in the crystallographic shear (CS) structure of the ferri-Manganite (Sr0.61Pb0.18)(Fe0.75Mn0.25)O2.29, related to the cation deficient perovskite, has been determined by careful analysis of the boundaries between the two variants constituting the phasoid. High Resolution Electron Microscopy/HAADF-STEM images allow the structural mechanisms to be understood through the presence of structural units common to both phases, responsible of the incommensurate character observed in the electron diffraction patterns. The structural analysis allows for identifying different types of CS phases in the Pb−Sr−Fe(Mn)−O diagram and shows that the stabilization of the six-sided tunnels requires a higher A/B cationic ratio. A description of these phases is proposed through simple structural building units (SBU), based on chains of octahedra bordered by two pyramids. The (Sr0.61Pb0.18)(Fe0.75Mn0.25)O2.29 CS compound exhibits a strong antiferromagnetic and insulating behavior, similar to the Fe-2201 and terrace ferrites but differs by the presence of a hysteresis, with a small coercive field.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000274929000025	Publication Date	2010-01-19
	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	6	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 9.466; 2010 IF: 6.400
	Call Number	UA @ lucian @ c:irua:81800			Serial	1593
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	Author	Parsons, T.G.; d' Hondt, H.; Hadermann, J.; Hayward, M.A.
	Title	Synthesis and structural characterization of La_1-xA_xMnO_2.5 (A = Ba, Sr, Ca) phases: mapping the variants of the brownmillerite structure			Type	A1 Journal article
	Year	2009	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	21	Issue	22	Pages	5527-5538
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Analysis of the structural parameters of phases that adopt brownmillerite-type structures suggests the distribution of the different complex ordering schemes adopted within this structure type can be rationalized by considering both the size of the separation between the tetrahedral layers and the tetrahedral chain distortion angle. A systematic study using structural data obtained from La1−xAxMnO2,5 (A = Ba, Sr, Ca,) phases, prepared by the topotactic reduction of the analogous La1−xAxMnO3 perovskite phases, was performed to investigate this relationship. By manipulating the A-cation composition, both the tetrahedral layer separation and tetrahedral chain distortion angle in the La1−xAxMnO2,5 phases were controlled and from the data obtained a ¡°structure map¡± of the different brownmillerite variants was plotted as a function of these structural parameters. This map has been extended to include a wide range of reported brownmillerite phases showing the structural ideas presented are widely applicable. The complete structural characterization of La1−xAxMnO2,5 0.1 ¡Ü x ¡Ü 0.33, A = Ba; 0.15 ¡Ü x ¡Ü 0.5 A = Sr, and 0.22 ¡Ü x ¡Ü 0.5 A = Ca is described and includes compositions which exhibit complex intralayer ordered structures and Mn2+/Mn3+ charge ordering.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000271756400021	Publication Date	2009-10-29
	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	60	Open Access
	Notes	Iap Vi			Approved	Most recent IF: 9.466; 2009 IF: 5.368
	Call Number	UA @ lucian @ c:irua:79935			Serial	3435
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	Author	Colomer, J.-F.; Marega, R.; Traboulsi, H.; Meneghetti, M.; Van Tendeloo, G.; Bonifazi, D.
	Title	Microwave-assisted bromination of double-walled carbon nanotubes			Type	A1 Journal article
	Year	2009	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	21	Issue	20	Pages	4747-4749
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000270807800001	Publication Date	2009-09-28
	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				Approved	Most recent IF: 9.466; 2009 IF: 5.368
	Call Number	UA @ lucian @ c:irua:94504			Serial	2080
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	Author	Pop, N.; Pralong, V.; Caignaert, V.; Colin, J.F.; Malo, S.; Van Tendeloo, G.; Raveau, B.
	Title	Topotactic transformation of the cationic conductor Li₄Mo₅O₁₇ into a rock salt type oxide Li₁₂Mo₅O₁₇			Type	A1 Journal article
	Year	2009	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	21	Issue	14	Pages	3242-3250
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Intercalation of lithium in the ribbon structure Li4Mo5O17 has been achieved, using both electrochemistry and soft chemistry. The ab initio structure determination of the ¡°Mo−O¡± framework of Li12Mo5O17 shows that the [Mo5O17]¡Þ ribbons keep the same arrangement of edge sharing MoO6 octahedra and the same orientation as in the parent structure but that a topotactic antidistortion of the ribbons appears, as a result of the larger size of Mo4+ in ¡°Li12¡± compared to Mo6+ in ¡°Li4¡±. On the basis of bond valence calculations, it is observed that 12 octahedral sites are available for Li+ in the new structure so that an ordered hypothetical rock salt type structure can be proposed for Li12Mo5O17. After the first Li insertion, a stable reversible capacity of 100 mA¡¤h/g is maintained after 20 cycles. A complete structural reversibility leading back to the ribbon type Li4Mo5O17 structure is obtained using a very low rate of C/100. The exploration of the Li mobility in those oxides shows that Li4Mo5O17 is a cationic conductor with ¦Ò = 10−3.5 S/cm at 500 ¡ãC and Ea = 0.35 eV.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000268174400032	Publication Date	2009-06-24
	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	18	Open Access
	Notes				Approved	Most recent IF: 9.466; 2009 IF: 5.368
	Call Number	UA @ lucian @ c:irua:78285			Serial	3682
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	Author	Lisiecki, I.; Turner, S.; Bals, S.; Pileni, M.P.; Van Tendeloo, G.
	Title	The remarkable and intriguing resistance to oxidation of 2D ordered hcp Co nanocrystals: a new intrinsic property			Type	A1 Journal article
	Year	2009	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	21	Issue	12	Pages	2335-2338
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000267049200001	Publication Date	2009-05-14
	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	28	Open Access
	Notes	Iap-Vi; Esteem 026019			Approved	Most recent IF: 9.466; 2009 IF: 5.368
	Call Number	UA @ lucian @ c:irua:77887			Serial	2867
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	Author	Hadermann, J.; Abakumov, A.M.; Van Rompaey, S.; Mankevich, A.S.; Korsakov, I.E.
	Title	Comment on ALaMn₂O_6-y (A = K, Rb): novel ferromagnetic manganites exhibiting negative giant magnetoresistance			Type	Editorial
	Year	2009	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	21	Issue	9	Pages	2000-2001
	Keywords	Editorial; Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000265781000036	Publication Date	2009-04-14
	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	4	Open Access
	Notes				Approved	Most recent IF: 9.466; 2009 IF: 5.368
	Call Number	UA @ lucian @ c:irua:77055			Serial	411
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	Author	Caignaert, V.; Abakumov, A.M.; Pelloquin, D.; Pralong, V.; Maignan, A.; Van Tendeloo, G.; Raveau, B.
	Title	A new mixed-valence ferrite with a cubic structure, YBaFe₄O₇: spin-glass-like behavior			Type	A1 Journal article
	Year	2009	Publication	Chemistry of materials	Abbreviated Journal	Chem Mater
	Volume	21	Issue	6	Pages	1116-1122
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	A new mixed-valence ferrite, YBaFe4O7, has been synthesized. Its unique cubic structure, with a = 8.9595(2) Å, is closely related to that of the hexagonal 114 oxides YBaCo4O7 and CaBaFe4O7. It consists of corner-sharing FeO4 tetrahedra, forming triangular and kagome layers parallel to (111)C. In fact, the YBaFe4O7 and CaBaFe4O7 structures can be described as two different ccc and chch close packings of [BaO3]∞ and [O4]∞ layers, respectively, whose tetrahedral cavities are occupied by Fe2+/Fe3+ cations. The local structure of YBaFe4O7 is characterized by a large amount of stacking faults originating from the presence of hexagonal layers in the ccc cubic close-packed YBaFe4O7 structure. In this way, they belong to the large family of spinels and hexagonal ferrites studied for their magnetic properties. Differently from all the ferrites and especially from CaBaFe4O7, which are ferrimagnetic, YBaFe4O7 is an insulating spin glass with Tg = 50 K.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000264310900019	Publication Date	2009-02-25
	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	39	Open Access
	Notes	Esteem 026019			Approved	Most recent IF: 9.466; 2009 IF: 5.368
	Call Number	UA @ lucian @ c:irua:76432			Serial	2325
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