Browsing by Author "Huijben, M."

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Critical thickness and orbital ordering in ultrathin La(0.7)Sr(0.3)MnO(3) films
(2008-09-01)
Huijben, M.
;
Martin, L. W.
;
Chu, Y. -H.
;
Holcomb, M. B.
;
Yu, P.
Detailed analysis of transport, magnetism, and x-ray absorption spectroscopy measurements on ultrathin La(0.7)Sr(0.3)MnO(3) films with thicknesses from 3 to 70 unit cells resulted in the identification of a lower critical thickness for a nonmetallic nonferromagnetic layer at the interface with the SrTiO(3) (001) substrate of only three unit cells (similar to 12 angstrom). Furthermore, linear-dichroism measurements demonstrate the presence of a preferred (x(2)-y(2)) in-plane orbital ordering for all layer thicknesses without any orbital reconstruction at the interface. A crucial requirement for the accurate study of these ultrathin films is a controlled growth process, offering the coexistence of layer-by-layer growth and bulklike magnetic/transport properties.
Critical thickness and orbital ordering in ultrathin La0.7Sr0.3MnO3 films
(2008-09-01)
Huijben, M.
;
Martin, L. W.
;
Chu, Y. -H.
;
Holcomb, M. B.
;
Yu, P.
Detailed analysis of transport, magnetism, and x-ray absorption spectroscopy measurements on ultrathin La0.7Sr0.3MnO3 films with thicknesses from 3 to 70 unit cells resulted in the identification of a lower critical thickness for a nonmetallic nonferromagnetic layer at the interface with the SrTiO3 (001) substrate of only three unit cells (similar to 12 angstrom). Furthermore, linear-dichroism measurements demonstrate the presence of a preferred (x(2)-y(2)) in-plane orbital ordering for all layer thicknesses without any orbital reconstruction at the interface. A crucial requirement for the accurate study of these ultrathin films is a controlled growth process, offering the coexistence of layer-by-layer growth and bulklike magnetic/transport properties.
Deterministic control of ferroelastic switching in multiferroic materials
(2009-12-01)
Balke, N.
;
Choudhury, S.
;
Jesse, S.
;
Huijben, M.
;
Chu, Y. H.
Multiferroic materials showing coupled electric, magnetic and elastic orderings provide a platform to explore complexity and new paradigms for memory and logic devices. Until now, the deterministic control of non-ferroelectric order parameters in multiferroics has been elusive. Here, we demonstrate deterministic ferroelastic switching in rhombohedral BiFeO(3) by domain nucleation with a scanning probe. We are able to select among final states that have the same electrostatic energy, but differ dramatically in elastic or magnetic order, by applying voltage to the probe while it is in lateral motion. We also demonstrate the controlled creation of a ferrotoroidal order parameter. The ability to control local elastic, magnetic and torroidal order parameters with an electric field will make it possible to probe local strain and magnetic ordering, and engineer various magnetoelectric, domain-wall-based and strain-coupled devices.
Interface Ferromagnetism and Orbital Reconstruction in BiFeO(3)-La(0.7)Sr(0.3)MnO(3) Heterostructures
(2010-07-06)
Yu, P.
;
Lee, J. -S.
;
Okamoto, S.
;
Rossell, M. D.
;
Huijben, M.
We report the formation of a novel ferromagnetic state in the antiferromagnet BiFeO(3) at the interface with ferromagnet La(0.7)Sr(0.3)MnO(3). Using x-ray magnetic circular dichroism at Mn and Fe L(2,3) edges, we discovered that the development of this ferromagnetic spin structure is strongly associated with the onset of a significant exchange bias. Our results demonstrate that the magnetic state is directly related to an electronic orbital reconstruction at the interface, which is supported by the linearly polarized x-ray absorption measurement at the oxygen K edge.
Interface Ferromagnetism and Orbital Reconstruction in BiFeO3-La0.7Sr0.3MnO3 Heterostructures
(2010-07-06)
Yu, P.
;
Lee, J. -S.
;
Okamoto, S.
;
Rossell, M. D.
;
Huijben, M.
We report the formation of a novel ferromagnetic state in the antiferromagnet BiFeO3 at the interface with ferromagnet La0.7Sr0.3MnO3. Using x-ray magnetic circular dichroism at Mn and Fe L-2,L-3 edges, we discovered that the development of this ferromagnetic spin structure is strongly associated with the onset of a significant exchange bias. Our results demonstrate that the magnetic state is directly related to an electronic orbital reconstruction at the interface, which is supported by the linearly polarized x-ray absorption measurement at the oxygen K edge.
Probing the evolution of antiferromagnetism in multiferroics
(2010-04-01)
Holcomb, M. B.
;
Martin, L. W.
;
Scholl, A.
;
He, Q.
;
Yu, P.
This study delineates the evolution of magnetic order in epitaxial films of the room-temperature multiferroic BiFeO(3) system. Using angle-and temperature-dependent dichroic measurements and spectromicroscopy, we have observed that the antiferromagnetic order in the model multiferroic BiFeO(3) evolves systematically as a function of thickness and strain. Lattice-mismatch-induced strain is found to break the easy-plane magnetic symmetry of the bulk and leads to an easy axis of magnetization which can be controlled through strain. Understanding the evolution of magnetic structure and how to manipulate the magnetism in this model multiferroic has significant implications for utilization of such magnetoelectric materials in future applications.
Suppression of Octahedral Tilts and Associated Changes in Electronic Properties at Epitaxial Oxide Heterostructure Interfaces
(2010-08-19)
Borisevich, A. Y.
;
Chang, H. J.
;
Huijben, M.
;
Oxley, M. P.
;
Okamoto, S.
Epitaxial oxide interfaces with broken translational symmetry have emerged as a central paradigm behind the novel behaviors of oxide superlattices. Here, we use scanning transmission electron microscopy to demonstrate a direct, quantitative unit-cell-by-unit-cell mapping of lattice parameters and oxygen octahedral rotations across the BiFeO(3)-La(0.7)Sr(0.3)MnO(3) interface to elucidate how the change of crystal symmetry is accommodated. Combined with low-loss electron energy loss spectroscopy imaging, we demonstrate a mesoscopic antiferrodistortive phase transition near the interface in BiFeO(3) and elucidate associated changes in electronic properties in a thin layer directly adjacent to the interface.
Ultrathin Limit of Exchange Bias Coupling at Oxide Multiferroic/Ferromagnetic Interfaces
(2013-09-14)
Huijben, M.
;
Yu, P.
;
Martin, L. W.
;
Molegraaf, H. J. A.
;
Chu, Y. -H.