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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 (up) 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
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000291197400001 Publication Date 2011-06-03
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 12 Open Access
Notes Approved Most recent IF: 3.836; 2011 IF: 3.691
Call Number UA @ lucian @ c:irua:90080 Serial 3107
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Author Fang, C.M.; van Huis, M.A.; Thijsse, B.J.; Zandbergen, H.W.
Title Stability and crystal structures of iron carbides : a comparison between the semi-empirical modified embedded atom method and quantum-mechanical DFT calculations Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 85 Issue 5 Pages 054116-054116,7
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Iron carbides play a crucial role in steel manufacturing and processing and to a large extent determine the physical properties of steel products. The modified embedded atom method (MEAM) in combination with Lee's Fe-C potential is a good candidate for molecular dynamics simulations on larger Fe-C systems. Here, we investigate the stability and crystal structures of pure iron and binary iron carbides using MEAM and compare them with the experimental data and quantum-mechanical density functional theory calculations. The analysis shows that the Fe-C potential gives reasonable results for the relative stability of iron and iron carbides. The performance of MEAM for the prediction of the potential energy and the calculated lattice parameters at elevated temperature for pure iron phases and cementite are investigated as well. The conclusion is that Lee's MEAM Fe-C potential provides a promising basis for further molecular dynamics simulations of Fe-C alloys and steels at lower temperatures (up to 800 K).
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000300931900004 Publication Date 2012-02-29
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 18 Open Access
Notes Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:97201 Serial 3117
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Author Potapov, P.L.; Kulkova, S.E.; Schryvers, D.; Verbeeck, J.
Title Structural and chemical effects on EELS L3,2 ionization edges in Ni-based intermetallic compounds Type A1 Journal article
Year 2001 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 64 Issue Pages 184110,1-9
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000172239400038 Publication Date 2002-07-27
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 44 Open Access
Notes Approved Most recent IF: 3.836; 2001 IF: NA
Call Number UA @ lucian @ c:irua:48393 Serial 3192
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Author Lobanov, M.V.; Balagurov, A.M.; Pomjakushin, V.J.; Fischer, P.; Gutmann, M.; Abakumov, A.M.; D'yachenko, O.G.; Antipov, E.V.; Lebedev, O.I.; Van Tendeloo, G.
Title Structural and magnetic properties of the colossal magnetoresistance perovskite La0.85Ca0.15MnO3 Type A1 Journal article
Year 2000 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 61 Issue 13 Pages 8941-8949
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000086597400059 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 47 Open Access
Notes Approved Most recent IF: 3.836; 2000 IF: NA
Call Number UA @ lucian @ c:irua:54735 Serial 3197
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Author Turner, S.; Lebedev, O.I.; Verbeeck, J.; Gehrke, K.; Moshnyaga, V.; Van Tendeloo, G.
Title Structural phase transition and spontaneous interface reconstruction in La2/3Ca1/3MnO3/BaTiO3 superlattices Type A1 Journal article
Year 2013 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 87 Issue 3 Pages 035418-8
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract (La2/3Ca1/3MnO3)n/(BaTiO3)m (LCMOn/BTOm) superlattices on MgO and SrTiO3 substrates with different layer thicknesses (n = 10, 38, 40 and m = 5, 18, 20) have been grown by metal organic aerosol deposition (MAD) and have been fully characterized down to the atomic scale to study the interface characteristics. Scanning transmission electron microscopy combined with spatially resolved electron energy-loss spectroscopy provides clear evidence for the existence of atomically sharp interfaces in MAD grown films, which exhibit epitaxial growth conditions, a uniform normal strain, and a fully oxidized state. Below a critical layer thickness the LCMO structure is found to change from the bulk Pnma symmetry to a pseudocubic R3̅ c symmetry. An atomically flat interface reconstruction consisting of a single Ca-rich atomic layer is observed on the compressively strained BTO on LCMO interface, which is thought to partially neutralize the total charge from the alternating polar atomic layers in LCMO as well as relieving strain at the interface. No interface reconstruction is observed at the tensile strained LCMO on BTO interface.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000313940400008 Publication Date 2013-01-23
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 12 Open Access
Notes FWO; Hercules; Countatoms Approved Most recent IF: 3.836; 2013 IF: 3.664
Call Number UA @ lucian @ c:irua:106180 Serial 3245
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Author Lebedev, O.I.; Verbeeck, J.; Van Tendeloo, G.; Shapoval, O.; Belenchuk, A.; Moshnyaga, V.; Damaschke, B.; Samwer, K.
Title Structural phase transitions and stress accommodation in (La0.67Ca0.33MnO3)1.x:(MgO)x composite films Type A1 Journal article
Year 2002 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 66 Issue 10 Pages 104421,1-10
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Composite (La0.67Ca0.33MnO3)(1-x):(MgO)(x) films were prepared by metalorganic aerosol deposition on a (100)MgO substrate for different concentrations of the (MgO) phase (0less than or equal toxless than or equal to0.8). At xapproximate to0.3 a percolation threshold in conductivity is reached, at which an infinite insulating MgO cluster forms around the La0.67Ca0.33MnO3 grains. This yields a drastic increase of the electrical resistance for films with x>0.3. The film structure is characterized by x-ray diffraction and transmission electron microscopy. The local structure of the La0.67Ca0.33MnO3 within the film depends on the MgO concentration which grows epitaxially along the domain boundaries. A different structural phase transition from the orthorhombic Pnma structure to an unusual rhombohedral R (3) over barc structure at the percolation threshold xapproximate to0.3 is found for La0.67Ca0.33MnO3. A three-dimensional stress accommodation in thick films through a phase transition is suggested.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000178460900060 Publication Date 2002-09-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 48 Open Access
Notes Approved Most recent IF: 3.836; 2002 IF: NA
Call Number UA @ lucian @ c:irua:54740 Serial 3250
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Author Lebedev, O.I.; Van Tendeloo, G.; Amelinckx, S.; Leibold, B.; Habermeier, H.-U.
Title Structure and microstructure of La1-xCaxMnO3- thin films prepared by pulsed layer deposition Type A1 Journal article
Year 1998 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 58 Issue 12 Pages 8065-8074
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000076130500085 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 131 Open Access
Notes Approved Most recent IF: 3.836; 1998 IF: NA
Call Number UA @ lucian @ c:irua:25679 Serial 3288
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Author Lebedev, O.I.; Van Tendeloo, G.; Cristiani, G.; Habermeier, H.-U.; Matveev, A.T.
Title Structure-properties relationship in ferromagnetic superconducting RuSr2GdCu2O8 Type A1 Journal article
Year 2005 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 71 Issue Pages 134523,1-8
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000228761800097 Publication Date 2005-04-28
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 16 Open Access
Notes Iap V-1 Approved Most recent IF: 3.836; 2005 IF: 3.185
Call Number UA @ lucian @ c:irua:54747 Serial 3316
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Author Lebedev, O.I.; Van Tendeloo, G.; Licci, F.; Gilioli, E.; Gauzzi, A.; Prodi, A.; Marezio, M.
Title Superconductivity and microstructure of YSr2Cu3O6.875 Type A1 Journal article
Year 2002 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 66 Issue Pages 132510,1-4
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000179067900042 Publication Date 2002-10-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 9 Open Access
Notes Approved Most recent IF: 3.836; 2002 IF: NA
Call Number UA @ lucian @ c:irua:54742 Serial 3371
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Author Titantah, J.T.; Lamoen, D.
Title Technique for the sp2/sp3 characterization of carbon materials: ab initio calculation of near-edge structure in electron energy-loss spectra Type A1 Journal article
Year 2004 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 70 Issue Pages 033101
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000223716600040 Publication Date 2004-08-31
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 41 Open Access
Notes Approved Most recent IF: 3.836; 2004 IF: 3.075
Call Number UA @ lucian @ c:irua:47374 Serial 3471
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Author Titantah, J.T.; Lamoen, D.; Schowalter, M.; Rosenauer, A.
Title Temperature effect on the 002 structure factor of ternary Ga1-xInxAs crystals Type A1 Journal article
Year 2007 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 76 Issue 7 Pages 073303,1-4
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000249155300011 Publication Date 2007-08-03
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 3 Open Access
Notes Approved Most recent IF: 3.836; 2007 IF: 3.172
Call Number UA @ lucian @ c:irua:66116 Serial 3499
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Author Milants, K.; Hendrickx, P.; Verheyden, J.; Barancira, T.; Deweerd, W.; Pattyn, H.; Bukshpan, S.; Vermeiren, F.; Van Tendeloo, G.
Title 133Xe(Cs) Mössbauer measurements on Ar, Ne, Kr, Xe, Rb, and Cs inclusions in W and Mo Type A1 Journal article
Year 1997 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 55 Issue 5 Pages 2831-2839
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos A1997WG88600034 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121; 0163-1829 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 2 Open Access
Notes Approved Most recent IF: 3.836; 1997 IF: NA
Call Number UA @ lucian @ c:irua:21422 Serial 3512
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Author Tsirlin, A.A.; Abakumov, A.M.; Ritter, C.; Rosner, H.
Title (CuCl)LaTa2O\text{7} and quantum phase transition in the (CuX)LaM2O7 family (X=Cl, Br; M=Nb, Ta) Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 6 Pages 064440-12
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We apply neutron diffraction, high-resolution synchrotron x-ray diffraction, magnetization measurements, electronic structure calculations, and quantum Monte-Carlo simulations to unravel the structure and magnetism of (CuCl)LaTa2O7. Despite the pseudo-tetragonal crystallographic unit cell, this compound features an orthorhombic superstructure, similar to the Nb-containing (CuX)LaNb2O7 with X = Cl and Br. The spin lattice entails dimers formed by the antiferromagnetic fourth-neighbor coupling J(4), as well as a large number of nonequivalent interdimer couplings quantified by an effective exchange parameter J(eff). In (CuCl)LaTa2O7, the interdimer couplings are sufficiently strong to induce the long-range magnetic order with the Neel temperature T-N similar or equal to 7 K and the ordered magnetic moment of 0.53 mu(B), as measured with neutron diffraction. This magnetic behavior can be accounted for by J(eff)/J(4) similar or equal to 1.6 and J(4) similar or equal to 16 K. We further propose a general magnetic phase diagram for the (CuCl)LaNb2O7-type compounds, and explain the transition from the gapped spin-singlet (dimer) ground state in (CuCl)LaNb2O7 to the long-range antiferromagnetic order in (CuCl)LaTa2O7 and (CuBr)LaNb2O7 by an increase in the magnitude of the interdimer couplings J(eff)/J(4), with the (CuCl)LaM2O7 (M = Nb, Ta) compounds lying on different sides of the quantum critical point that separates the singlet and long-range-ordered magnetic ground states.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000308127600006 Publication Date 2012-08-29
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 6 Open Access
Notes Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:101886 Serial 3526
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Author Verbeeck, J.; Lebedev, O.I.; Van Tendeloo, G.; Mercey, B.
Title SrTiO3(100)/(LaMnO3)m(SrMnO3)n layered heterostructures: a combined EELS and TEM study Type A1 Journal article
Year 2002 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 66 Issue 18 Pages 184426
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Epitaxially grown heterostructures consisting of alternating layers of LaMnO(3) (LMO, 9 or 15 unit cells) and SrMnO(3) (SMO, 4 or 6 unit cells) on a SrTiO(3)(100) (STO(100)) substrate have been studied by a combination of high resolution transmission electron microscopy (HRTEM), electron diffraction, quantitative electron energy loss spectroscopy (EELS) with model fitting, energy filtered TEM (EFTEM) and imaging spectroscopy on an atomic scale. The combination of these techniques is necessary for the structural, chemical, and electronic characterization of these heterostructures. A model is proposed containing chemically and structurally sharp interfaces. The SrMnO(3) layers are stabilized in a Pm3m structure between two LMO layers. Tensile stress causes oxygen deficiency in the SMO layers increasing the number of 3d electrons on the Mn sites to resemble the Mn(3+) sites in LMO. The energy loss near edge structure (ELNES) of O and Mn is compared for both LMO and SMO layers and shows that the Mn-O bonds have a partially covalent character. The absence of a strong valency effect in the Mn ELNES is due to the oxygen vacancies in SMO.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000179633100062 Publication Date 2002-11-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 32 Open Access
Notes Approved Most recent IF: 3.836; 2002 IF: NA
Call Number UA @ lucian @ c:irua:54741 Serial 3563
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Author Pauwels, B.; Van Tendeloo, G.; Zhurkin, E.; Hou, M.; Verschoren, G.; Kuhn, L.T.; Bouwen, W.; Lievens, P.
Title Transmission electron microscopy and Monte Carlo simulations of ordering in Au-Cu clusters produced in a laser vaporization source Type A1 Journal article
Year 2001 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 63 Issue Pages 165406,1-9
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000168343400086 Publication Date 2002-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829;1095-3795; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 64 Open Access
Notes Approved Most recent IF: 3.836; 2001 IF: NA
Call Number UA @ lucian @ c:irua:54737 Serial 3705
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Author Werner, R.; Raisch, C.; Leca, V.; Ion, V.; Bals, S.; Van Tendeloo, G.; Chasse, T.; Kleiner, R.; Koelle, D.
Title Transport, magnetic, and structural properties of La0.7Ce0.3MnO3 thin films: evidence for hole-doping Type A1 Journal article
Year 2009 Publication Physical review : B : solid state Abbreviated Journal Phys Rev B
Volume 79 Issue 5 Pages 054416,1-054416,8
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Cerium-doped manganite thin films were grown epitaxially by pulsed laser deposition at 720 °C and oxygen pressure pO2=125 Pa and were subjected to different annealing steps. According to x-ray diffraction (XRD) data, the formation of CeO2 as a secondary phase could be avoided for pO28 Pa. However, transmission electron microscopy shows the presence of CeO2 nanoclusters even in those films which appear to be single phase in XRD. With O2 annealing, the metal-to-insulator transition temperature increases, while the saturation magnetization decreases and stays well below the theoretical value for electron-doped La0.7Ce0.3MnO3 with mixed Mn3+/Mn2+ valences. The same trend is observed with decreasing film thickness from 100 to 20 nm, indicating a higher oxygen content for thinner films. Hall measurements on a film which shows a metal-to-insulator transition clearly reveal holes as dominating charge carriers. Combining data from x-ray photoemission spectroscopy, for determination of the oxygen content, and x-ray absorption spectroscopy (XAS), for determination of the hole concentration and cation valences, we find that with increasing oxygen content the hole concentration increases and Mn valences are shifted from 2+ to 4+. The dominating Mn valences in the films are Mn3+ and Mn4+, and only a small amount of Mn2+ ions can be observed by XAS. Mn2+ and Ce4+ XAS signals obtained in surface-sensitive total electron yield mode are strongly reduced in the bulk-sensitive fluorescence mode, which indicates hole-doping in the bulk for those films which do show a metal-to-insulator transition.
Address
Corporate Author Thesis
Publisher Place of Publication Lancaster, Pa Editor
Language Wos 000263815400057 Publication Date 2009-02-13
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 25 Open Access
Notes Esteem 026019; Fwo Approved Most recent IF: 3.836; 2009 IF: 3.475
Call Number UA @ lucian @ c:irua:76221 Serial 3725
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Author van den Heuvel, W.; Tikhomirov, V.K.; Kirilenko, D.; Schildermans, N.; Chibotaru, L.F.; Vanacken, J.; Gredin, P.; Mortier, M.; Van Tendeloo, G.; Moshchalkov, V.V.
Title Ultralow blocking temperature and breakdown of the giant spin model in Er3+-doped nanoparticles Type A1 Journal article
Year 2010 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 82 Issue 9 Pages 094421-094421,8
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The magnetization of luminescent Er3+-doped PbF2 nanoparticles (formula Er0.3Pb0.7F2.3) has been studied. Despite the high concentration of the doping Er3+ ions and relatively large size (8 nm) of these nanoparticles we have found no deviation between field-cooled and zero-field-cooled magnetization curves down to T=0.35 K, which points out an ultralow blocking temperature for the reversal of magnetization. We also have found strongly deviating magnetization curves M(H/T) for different temperatures T. These results altogether show that the investigated nanoparticles are not superparamagnetic, but rather each Er3+ ion in these nanoparticles is found in a paramagnetic state down to very low temperatures, which implies the breakdown of the Néel-Brown giant spin model in the case of these nanoparticles. Calculations of magnetization within a paramagnetic model of noninteracting Er3+ ions completely support this conclusion. Due to the ultralow blocking temperature, these nanoparticles have a potential for magnetic field-induced nanoscale refrigeration with an option of their optical localization and temperature control.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000281773300005 Publication Date 2010-09-13
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 11 Open Access
Notes Fwo Approved Most recent IF: 3.836; 2010 IF: 3.774
Call Number UA @ lucian @ c:irua:85423 Serial 3796
Permanent link to this record
 

 
Author Juchtmans, R.; Béché, A.; Abakumov, A.; Batuk, M.; Verbeeck, J.
Title Using electron vortex beams to determine chirality of crystals in transmission electron microscopy Type A1 Journal article
Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 91 Issue 91 Pages 094112
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We investigate electron vortex beams elastically scattered on chiral crystals. After deriving a general expression for the scattering amplitude of a vortex electron, we study its diffraction on point scatterers arranged on a helix. We derive a relation between the handedness of the helix and the topological charge of the electron vortex on one hand and the symmetry of the higher-order Laue zones in the diffraction pattern on the other for kinematically and dynamically scattered electrons. We then extend this to atoms arranged on a helix as found in crystals which belong to chiral space groups and propose a method to determine the handedness of such crystals by looking at the symmetry of the diffraction pattern. In contrast to alternative methods, our technique does not require multiple scattering, which makes it possible to also investigate extremely thin samples in which multiple scattering is suppressed. In order to verify the model, elastic scattering simulations are performed, and an experimental demonstration on Mn2Sb2O7 is given in which we find the sample to belong to the right-handed variant of its enantiomorphic pair. This demonstrates the usefulness of electron vortex beams to reveal the chirality of crystals in a transmission electron microscope and provides the required theoretical basis for further developments in this field.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000352017000002 Publication Date 2015-03-27
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 54 Open Access
Notes Fwo; 312483 Esteem2; 278510 Vortex; esteem2jra1; esteem2jra2 ECASJO_; Approved Most recent IF: 3.836; 2015 IF: 3.736
Call Number c:irua:125512 c:irua:125512 Serial 3825
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Author Juchtmans, R.; Verbeeck, J.
Title Orbital angular momentum in electron diffraction and its use to determine chiral crystal symmetries Type A1 Journal article
Year 2015 Publication Physical review: B: condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 92 Issue 92 Pages 134108
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract In this work we present an alternative way to look at electron diffraction in a transmission electron microscope.

Instead of writing the scattering amplitude in Fourier space as a set of plane waves,we use the cylindrical Fourier transform to describe the scattering amplitude in a basis of orbital angular momentum (OAM) eigenstates. We show how working in this framework can be very convenient when investigating, e.g., rotation and screw-axis symmetries. For the latter we find selection rules on the OAM coefficients that unambiguously reveal the handedness of the screw axis. Detecting the OAM coefficients of the scattering amplitude thus offers the possibility to detect the handedness of crystals without the need for dynamical simulations, the thickness of the sample, nor the exact crystal structure. We propose an experimental setup to measure the OAM components where an image of the crystal is taken after inserting a spiral phase plate in the diffraction plane and perform multislice simulations on α quartz to demonstrate how the method indeed reveals the chirality. The experimental feasibility of the technique is discussed together with its main advantages with respect to chirality determination of screw axes. The method shows how the use of a spiral phase plate can be extended from a simple phase imaging technique to a tool to measure the local OAM decomposition of an electron wave, widening the field of interest well beyond chiral space group determination.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000362893100002 Publication Date 2015-10-14
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 16 Open Access
Notes The authors acknowledge support from the FWO (As- pirant Fonds Wetenschappelijk Onderzoek–Vlaanderen), the EU under the Seventh Framework Program (FP7) under a contract for an Integrated Infrastructure Initiative, Reference No. 312483-ESTEEM2, and ERC Starting Grant No. 278510 VORTEX; esteem2jra1; ECASJO; Approved Most recent IF: 3.836; 2015 IF: 3.736
Call Number c:irua:129417 c:irua:129417UA @ admin @ c:irua:129417 Serial 4089
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Author Kleibert, A.; Balan, A.; Yanes, R.; Derlet, P.M.; Vaz, C.A.F.; Timm, M.; Fraile Rodríguez, A.; Béché, A.; Verbeeck, J.; Dhaka, R.S.; Radovic, M.; Nowak, U.; Nolting, F.
Title Direct observation of enhanced magnetism in individual size- and shape-selected 3d transition metal nanoparticles Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 95 Issue 95 Pages 195404
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Magnetic nanoparticles are critical building blocks for future technologies ranging from nanomedicine to spintronics. Many related applications require nanoparticles with tailored magnetic properties. However, despite significant efforts undertaken towards this goal, a broad and poorly understood dispersion of magnetic properties is reported, even within monodisperse samples of the canonical ferromagnetic 3d transition metals. We address this issue by investigating the magnetism of a large number of size- and shape-selected, individual nanoparticles of Fe, Co, and Ni using a unique set of complementary characterization techniques. At room temperature, only superparamagnetic behavior is observed in our experiments for all Ni nanoparticles within the investigated sizes, which range from 8 to 20 nm. However, Fe and Co nanoparticles can exist in two distinct magnetic states at any size in this range: (i) a superparamagnetic state, as expected from the bulk and surface anisotropies known for the respective materials and as observed for Ni, and (ii) a state with unexpected stable magnetization at room temperature. This striking state is assigned to significant modifications of the magnetic properties arising from metastable lattice defects in the core of the nanoparticles, as concluded by calculations and atomic structural characterization. Also related with the structural defects, we find that the magnetic state of Fe and Co nanoparticles can be tuned by thermal treatment enabling one to tailor their magnetic properties for applications. This paper demonstrates the importance of complementary single particle investigations for a better understanding of nanoparticle magnetism and for full exploration of their potential for applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000400665300002 Publication Date 2017-05-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 21 Open Access OpenAccess
Notes We thank A. Weber, R. Schelldorfer, and J. Krbanjevic (Paul Scherrer Institut) for technical assistance. This paper was supported by the Swiss Nanoscience Institute, University of Basel. A.F.R. acknowledges support from the MICIIN “Ramón y Cajal” Programme. A.B. and J.V. acknowledge funding from the European Union under the European Research Council (ERC) Starting Grant No. 278510 VORTEX and under a contract for Integrated Infrastructure Initiative ESTEEM2 No. 312483. R.Y. and U.N. thank the Deutsche Forschungsgemeinschaft for financial support via Sonderforschungsbereich 1214. Part of this work was performed at the Surface/Interface: Microscopy (SIM) beamline of the Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland. Approved Most recent IF: 3.836
Call Number EMAT @ emat @ c:irua:143634UA @ admin @ c:irua:143634 Serial 4575
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Author Tsirlin, A.A.; Rousochatzakis, I.; Filimonov, D.; Batuk, D.; Frontzek, M.; Abakumov, A.M.
Title Spin-reorientation transitions in the Cairo pentagonal magnet Bi4Fe5O13F Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 96 Issue 9 Pages 094420
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We show that interlayer spins play a dual role in the Cairo pentagonal magnet Bi4Fe5O13F, on one hand mediating the three-dimensional magnetic order, and on the other driving spin-reorientation transitions both within and between the planes. The corresponding sequence of magnetic orders unraveled by neutron diffraction and Mossbauer spectroscopy features two orthogonal magnetic structures described by opposite local vector chiralities, and an intermediate, partly disordered phase with nearly collinear spins. A similar collinear phase has been predicted theoretically to be stabilized by quantum fluctuations, but Bi4Fe5O13F is very far from the relevant parameter regime. While the observed in-plane reorientation cannot be explained by any standard frustration mechanism, our ab initio band-structure calculations reveal strong single-ion anisotropy of the interlayer Fe3+ spins that turns out to be instrumental in controlling the local vector chirality and the associated interlayer order.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000411161700002 Publication Date 2017-09-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 7 Open Access OpenAccess
Notes We are grateful to J.-M. Perez-Mato and Dmitry Khalyavin for valuable discussions on the magnetic structures and symmetries. D.F. and A.A. are grateful to the Russian Science Foundation (Grant No. 14-13-00680) for support. A.T. was supported by the Federal Ministry for Education and Research through the Sofja Kovalevskaya Award of the Alexander von Humboldt Foundation. This work is based on experiments performed at the Swiss spallation neutron source SINQ, Paul Scherrer Institut, Villigen, Switzerland. Approved Most recent IF: 3.836
Call Number EMAT @ emat @c:irua:146748 Serial 4774
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Author Augustyns, V.; van Stiphout, K.; Joly, V.; Lima, T.A.L.; Lippertz, G.; Trekels, M.; Menendez, E.; Kremer, F.; Wahl, U.; Costa, A.R.G.; Correia, J.G.; Banerjee, D.; Gunnlaugsson, H.P.; von Bardeleben, J.; Vickridge, I.; Van Bael, M.J.; Hadermann, J.; Araujo, J.P.; Temst, K.; Vantomme, A.; Pereira, L.M.C.
Title Evidence of tetragonal distortion as the origin of the ferromagnetic ground state in gamma-Fe nanoparticles Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 96 Issue 17 Pages 174410
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract <script type='text/javascript'>document.write(unpmarked('gamma-Fe and related alloys are model systems of the coupling between structure and magnetism in solids. Since different electronic states (with different volumes and magnetic ordering states) are closely spaced in energy, small perturbations can alter which one is the actual ground state. Here, we demonstrate that the ferromagnetic state of gamma-Fe nanoparticles is associated with a tetragonal distortion of the fcc structure. Combining a wide range of complementary experimental techniques, including low-temperature Mossbauer spectroscopy, advanced transmission electron microscopy, and synchrotron radiation techniques, we unambiguously identify the tetragonally distorted ferromagnetic ground state, with lattice parameters a = 3.76(2) angstrom and c = 3.50(2) angstrom, and a magnetic moment of 2.45(5) mu(B) per Fe atom. Our findings indicate that the ferromagnetic order in nanostructured gamma-Fe is generally associated with a tetragonal distortion. This observation motivates a theoretical reassessment of the electronic structure of gamma-Fe taking tetragonal distortion into account.'));
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000414525200005 Publication Date 2017-11-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 1 Open Access OpenAccess
Notes ; The authors thank the Fund for Scientific Research-Flanders, the Concerted Research Action of the KU Leuven (GOA/14/007), the KU Leuven BOF (STRT/14/002), the Hercules Foundation, the Portuguese Foundation for Science and Technology (CERN/FIS-NUC/0004/2015), and the European Union Seventh Framework through ENSAR2 (European Nuclear Science and Applications Research, Project No. 654002), and SPIRIT (Support of Public and Industrial Research Using Ion Beam Technology, Contract No. 227012). We acknowledge the European Synchrotron Radiation Facility (ESRF) for providing beam time (experiments 26-01-1018, 26-01-1057, 20-02-728, HC-1850, HC-2208), as well as C. Baehtz, N. Boudet, and N. Blancand for support during the experiments. We acknowledge the ISOLDE-CERN facility for providing beam time (experiment IS580) and technical assistance. The authors (L.M.C.P., F.K.) acknowledge the facilities and the scientific and technical assistance of the Australian Microscopy & Microanalysis Research Facility at the Centre for Advanced Microscopy, Australian National University. We also acknowledge the contribution of Prof. Mark Ridgway (Australian National University), who passed away before the work was completed. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:147387 Serial 4873
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Author Carmesin, C.; Schowalter, M.; Lorke, M.; Mourad, D.; Grieb, T.; Müller-Caspary, K.; Yacob, M.; Reithmaier, J.P.; Benyoucef, M.; Rosenauer, A.; Jahnke, F.
Title Interplay of morphology, composition, and optical properties of InP-based quantum dots emitting at the 1.55 \mum telecom wavelength Type A1 Journal article
Year 2017 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 96 Issue 23 Pages 235309
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract <script type='text/javascript'>document.write(unpmarked('Results for the development and detailed analysis of self-organized InAs/InAlGaAs/InP quantum dots suitable for single-photon emission at the 1.55 mu m telecom wavelength are reported. The structural and compositional properties of the system are obtained from high-resolution scanning transmission electron microscopy of individual quantum dots. The system is composed of almost pure InAs quantum dots embedded in quaternary InAlGaAs barrier material, which is lattice matched to the InP substrate. When using the measured results for a representative quantum-dot geometry as well as experimentally reconstructed alloy concentrations, a combination of strain-field and electronic-state calculations is able to reproduce the quantum-dot emission wavelength in agreement with the experimentally determined photoluminescence spectrum. The inhomogeneous broadening of the latter can be related to calculated variations of the emission wavelength for the experimentally deduced In-concentration fluctuations and size variations.'));
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000418654200009 Publication Date 2017-12-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 3 Open Access OpenAccess
Notes ; The authors gratefully acknowledge financial support from the Deutsche Forschungsgemeinschaft Project No. JA 14-1, the BMBF Projects Q.com-H No. 16KIS0111 and No. 16KIS0112, as well as computational resources from HLRN (Hannover, Berlin). ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:148505 Serial 4882
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Author Müller-Caspary, K.; Duchamp, M.; Roesner, M.; Migunov, V.; Winkler, F.; Yang, H.; Huth, M.; Ritz, R.; Simson, M.; Ihle, S.; Soltau, H.; Wehling, T.; Dunin-Borkowski, R.E.; Van Aert, S.; Rosenauer, A.
Title Atomic-scale quantification of charge densities in two-dimensional materials Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 98 Issue 12 Pages 121408
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The charge density is among the most fundamental solid state properties determining bonding, electrical characteristics, and adsorption or catalysis at surfaces. While atomic-scale charge densities have as yet been retrieved by solid state theory, we demonstrate both charge density and electric field mapping across a mono-/bilayer boundary in 2D MoS2 by momentum-resolved scanning transmission electron microscopy. Based on consistency of the four-dimensional experimental data, statistical parameter estimation and dynamical electron scattering simulations using strain-relaxed supercells, we are able to identify an AA-type bilayer stacking and charge depletion at the Mo-terminated layer edge.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000445508200004 Publication Date 2018-09-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 10 Open Access OpenAccess
Notes ; K.M.-C. acknowledges funding from the Initiative and Network Fund of the Helmholtz Association (VH-NG-1317) within the framework of the Helmholtz Young Investigator Group moreSTEM at Forschungszentrum Julich, Germany. ; Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:153621 Serial 5078
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Author Behera, B.C.; Jana, S.; Bhat, S.G.; Gauquelin, N.; Tripathy, G.; Kumar, P.S.A.; Samal, D.
Title Evidence for exchange bias coupling at the perovskite/brownmillerite interface in spontaneously stabilized SrCoO3-\delta/SrCoO2.5 bilayers Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 99 Issue 2 Pages 024425
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Interface effect in complex oxide thin-film heterostructures lies at the vanguard of current research to design technologically relevant functionality and explore emergent physical phenomena. While most of the previous works focus on the perovskite/perovskite heterostructures, the study of perovskite/brownmillerite interfaces remains in its infancy. Here, we investigate spontaneously stabilized perovskite-ferromagnet (SrCoO3-delta)/brownmillerite-antiferromagnet (SrCoO2.5) bilayer with T-N > T-C and discover an unconventional interfacial magnetic exchange bias effect. From magnetometry investigations, it is rationalized that the observed effect stems from the interfacial ferromagnet/antiferromagnet coupling. The possibility for coupled ferromagnet/spin-glass interface engendering such effect is ruled out. Strikingly, a finite coercive field persists in the paramagnetic state of SrCoO3-delta,whereas the exchange bias field vanishes at T-C . We conjecture the observed effect to be due to the effective external quenched staggered field provided by the antiferromagnetic layer for the ferromagnetic spins at the interface. Our results not only unveil a paradigm to tailor the interfacial magnetic properties in oxide heterostructures without altering the cations at the interface, but also provide a purview to delve into the fundamental aspects of exchange bias in such unusual systems, paving a big step forward in thin-film magnetism.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000456481900003 Publication Date 2019-01-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 2 Open Access OpenAccess
Notes ; We are grateful to Sachin Sarangi for his superb technical support during magnetic measurements. We thank Gopal Pradhan for fruitful discussion. We thank Zhicheng Zhong for reading the manuscript and for suggestions. We thank T. Som for extending laboratory facility. D.S. and B.C.B. acknowledge the financial support from Max-Planck Society through Max Planck Partner Group. S.G.B. acknowledges the INSPIRE Faculty Fellowship Programme (DSTO1899) for the financial support. ; Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:157562 Serial 5248
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Author Das, S.; Rata, A.D.; Maznichenko, I., V; Agrestini, I.S.; Pippel, E.; Gauquelin, N.; Verbeeck, J.; Chen, K.; Valvidares, S.M.; Vasili, H.B.; Herrero-Martin, J.; Pellegrin, E.; Nenkov, K.; Herklotz, A.; Ernst, A.; Mertig, I.; Hu, Z.; Doerr, K.
Title Low-field switching of noncollinear spin texture at La0.7Sr0.3MnO3-SrRuO3interfaces Type A1 Journal article
Year 2019 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 99 Issue 2 Pages 024416
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Interfaces of ferroic oxides can show complex magnetic textures which have strong impact on spintronics devices. This has been demonstrated recently for interfaces with insulating antiferromagnets such as BiFeO3. Here, noncollinear spin textures which can be switched in very low magnetic field are reported for conducting ferromagnetic bilayers of La0.7Sr0.3MnO3-SrRuO3 (LSMO-SRO). The magnetic order and switching are fundamentally different for bilayers coherently grown in reversed stacking sequence. The SRO top layer forms a persistent exchange spring which is antiferromagnetically coupled to LSMO and drives switching in low fields of a few milliteslas. Density functional theory reveals the crucial impact of the interface termination on the strength of Mn-Ru exchange coupling across the interface. The observation of an exchange spring agrees with ultrastrong coupling for the MnO2/SrO termination. Our results demonstrate low-field switching of noncollinear spin textures at an interface between conducting oxides, opening a pathway for manipulating and utilizing electron transport phenomena in controlled spin textures at oxide interfaces.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000455821400005 Publication Date 2019-01-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 19 Open Access OpenAccess
Notes ; The research in Halle was supported by Deutsche Forschungsgemeinschaft (DFG), SFB 762 Functional Oxide Interfaces (Projects No. A9 and No. B1). K.C. benefited from support of the DFG (Project 600575). Discussions with M. Trassin, M. Ziese, H. M. Christen, E.-J. Guo, F. Grcondciel, M. Bibes, and H. N. Lee are gratefully acknowledged. N. G. and J. V. acknowledge funding under the GOA project “Solarpaint” of the University of Antwerp. The Qu-Ant-EM microscope was partly funded by the Hercules fund from the Flemish Government. ; Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:156717 Serial 5255
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Author Kuo, C.-T.; Lin, S.-C.; Ghiringhelli, G.; Peng, Y.; De Luca, G.M.; Di Castro, D.; Betto, D.; Gehlmann, M.; Wijnands, T.; Huijben, M.; Meyer-Ilse, J.; Gullikson, E.; Kortright, J.B.; Vailionis, A.; Gauquelin, N.; Verbeeck, J.; Gerber, T.; Balestrino, G.; Brookes, N.B.; Braicovich, L.; Fadley, C.S.
Title Depth-resolved resonant inelastic x-ray scattering at a superconductor/half-metallic-ferromagnet interface through standing wave excitation Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 98 Issue 23 Pages 235146
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract We demonstrate that combining standing wave (SW) excitation with resonant inelastic x-ray scattering (RIXS) can lead to depth resolution and interface sensitivity for studying orbital and magnetic excitations in correlated oxide heterostructures. SW-RIXS has been applied to multilayer heterostructures consisting of a superconductor La1.85Sr0.15CuO4 (LSCO) and a half-metallic ferromagnet La0.67Sr0.33MnO3 (LSMO). Easily observable SW effects on the RIXS excitations were found in these LSCO/LSMO multilayers. In addition, we observe different depth distribution of the RIXS excitations. The magnetic excitations are found to arise from the LSCO/LSMO interfaces, and there is also a suggestion that one of the dd excitations comes from the interfaces. SW-RIXS measurements of correlated-oxide and other multilayer heterostructures should provide unique layer-resolved insights concerning their orbital and magnetic excitations, as well as a challenge for RIXS theory to specifically deal with interface effects.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000454160800004 Publication Date 2018-12-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 5 Open Access
Notes J.V. and N.G. acknowledge ˝ funding through the GOA project “Solarpaint” of the University of Antwerp. The microscope used in this work was partly funded by the Hercules Fund from the Flemish Government. Approved Most recent IF: 3.836
Call Number UA @ admin @ c:irua:156784 Serial 5363
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Author Savchenko, T.M.; Buzzi, M.; Howald, L.; Ruta, S.; Vijayakumar, J.; Timm, M.; Bracher, D.; Saha, S.; Derlet, P.M.; Béché, A.; Verbeeck, J.; Chantrell, R.W.; Vaz, C.A.F.; Nolting, F.; Kleibert, A.
Title Single femtosecond laser pulse excitation of individual cobalt nanoparticles Type A1 Journal article
Year 2020 Publication Physical Review B Abbreviated Journal Phys Rev B
Volume 102 Issue 20 Pages 205418
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Laser-induced manipulation of magnetism at the nanoscale is a rapidly growing research topic with potential for applications in spintronics. In this work, we address the role of the scattering cross section, thermal effects, and laser fluence on the magnetic, structural, and chemical stability of individual magnetic nanoparticles excited by single femtosecond laser pulses. We find that the energy transfer from the fs laser pulse to the nanoparticles is limited by the Rayleigh scattering cross section, which in combination with the light absorption of the supporting substrate and protective layers determines the increase in the nanoparticle temperature. We investigate individual Co nanoparticles (8 to 20 nm in size) as a prototypical model system, using x-ray photoemission electron microscopy and scanning electron microscopy upon excitation with single femtosecond laser pulses of varying intensity and polarization. In agreement with calculations, we find no deterministic or stochastic reversal of the magnetization in the nanoparticles up to intensities where ultrafast demagnetization or all-optical switching is typically reported in thin films. Instead, at higher fluences, the laser pulse excitation leads to photo-chemical reactions of the nanoparticles with the protective layer, which results in an irreversible change in the magnetic properties. Based on our findings, we discuss the conditions required for achieving laser-induced switching in isolated nanomagnets.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000589602000005 Publication Date 2020-11-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9950 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.7 Times cited 1 Open Access OpenAccess
Notes This work received funding by the Swiss National Foundation (SNF) (Grants No. 200021160186 and No. 2002153540), the Swiss Nanoscience Institute (SNI) (Grant No. SNI P1502), the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 737093 (FEMTOTERABYTE), and the COST Action CA17123 (MAGNETOFON). Part of this work was performed at the SIM beamline of the Swiss Light Source (SLS), Paul Scherrer Institut, Villigen, Switzerland. Part of the simulations were undertaken on the VIKING cluster, which is a high-performance compute facility provided by the University of York. We kindly acknowledge Anja Weber from PSI for preparation of substrates with marker structures. A.B. and Jo Verbeeck acknowledge funding through FWO Project No. G093417N (“Compressed sensing enabling low dose imaging in transmission electron microscopy”) from the Flanders Research Fund. Jo Verbeeck acknowledges funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. 823717 – ESTEEM3. S.S. acknowledges ETH Zurich Post-Doctoral fellowship and Marie Curie actions for people COFUND program.; esteem3JRA; esteem3reported Approved Most recent IF: 3.7; 2020 IF: 3.836
Call Number EMAT @ emat @c:irua:174273 Serial 6669
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Author Matsubara, M.; Amini, M.N.; Saniz, R.; Lamoen, D.; Partoens, B.
Title Attracting shallow donors : hydrogen passivation in (Al,Ga,In)-doped ZnO Type A1 Journal article
Year 2012 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 86 Issue 16 Pages 165207
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract The hydrogen interstitial and the substitutional AlZn, GaZn, and InZn are all shallow donors in ZnO and lead to n-type conductivity. Although shallow donors are expected to repel each other, we show by first-principles calculations that in ZnO these shallow donor impurities attract and form a complex, leading to a donor level deep in the band gap. This puts a limit on the n-type conductivity of (Al,Ga,In)-doped ZnO in the presence of hydrogen.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000310131300008 Publication Date 2012-10-22
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 7 Open Access
Notes Iwt; Fwo; Bof-Noi Approved Most recent IF: 3.836; 2012 IF: 3.767
Call Number UA @ lucian @ c:irua:101780 Serial 202
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Author Govaerts, K.; Park, K.; De Beule, C.; Partoens, B.; Lamoen, D.
Title Effect of Bi bilayers on the topological states of Bi2Se3 : a first-principles study Type A1 Journal article
Year 2014 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 90 Issue 15 Pages 155124
Keywords (up) A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract Bi2Se3 is a three-dimensional topological insulator which has been extensively studied because it has a single Dirac cone on the surface, inside a relatively large bulk band gap. However, the effect of two-dimensional topological insulator Bi bilayers on the properties of Bi2Se3 and vice versa, has not been explored much. Bi bilayers are often present between the quintuple layers of Bi2Se3, since (Bi2)n(Bi2Se3)m form stable ground-state structures. Moreover, Bi2Se3 is a good substrate for growing ultrathin Bi bilayers. By first-principles techniques, we first show that there is no preferable surface termination by either Bi or Se. Next, we investigate the electronic structure of Bi bilayers on top of, or inside a Bi2Se3 slab. If the Bi bilayers are on top, we observe a charge transfer to the quintuple layers that increases the binding energy of the surface Dirac cones. The extra states, originating from the Bi bilayers, were declared to form a topological Dirac cone, but here we show that these are ordinary Rashba-split states. This result, together with the appearance of a new Dirac cone that is localized slightly deeper, might necessitate the reinterpretation of several experimental results. When the Bi bilayers are located inside the Bi2Se3 slab, they tend to split the slab into two topological insulators with clear surface states. Interface states can also be observed, but an energy gap persists because of strong coupling between the neighboring quintuple layers and the Bi bilayers.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000343773200001 Publication Date 2014-10-20
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 30 Open Access
Notes ; We gratefully acknowledge financial support from the Research Foundation – Flanders (FWO-Vlaanderen). K.G. thanks the University of Antwerp for a Ph.D. fellowship. C.D.B. is an aspirant of the Flemish Science Foundation. This work was carried out using the HPC infrastructure at the University of Antwerp (CalcUA), a division of the Flemish Supercomputer Center VSC, supported financially by the Hercules Foundation and the Flemish Government (EWI Department). K.P. was supported by U.S. National Science Foundation Grant No. DMR-1206354. ; Approved Most recent IF: 3.836; 2014 IF: 3.736
Call Number UA @ lucian @ c:irua:119527 Serial 800
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