We utilize polarized neutron reflectometry in consort with ab initio based density functional the... more We utilize polarized neutron reflectometry in consort with ab initio based density functional theory calculations to study interface magnetoelectric coupling across a ferroelectric PbZr0.2Ti0.8O3 and magnetic La0.67Sr0.33MnO3 heterostructure.
Lattice mismatch induced epitaxial strain has been widely used to tune functional properties in c... more Lattice mismatch induced epitaxial strain has been widely used to tune functional properties in complex oxide heterostructures. Apart from the epitaxial strain, a large lattice mismatch also produces other effects...
Journal of physics. Condensed matter : an Institute of Physics journal, Oct 5, 2016
Multiferroic heterostructures composed of thin layers of ferromagnetic and ferroelectric perovski... more Multiferroic heterostructures composed of thin layers of ferromagnetic and ferroelectric perovskites have attracted considerable attention in recent years. We apply ab initio computational methods based on density functional theory to study the magnetoelectric coupling at the (0 0 1) interface between [Formula: see text] (LSMO) and [Formula: see text] (PZT). Our study demonstrates that the ferroelectric polarization of PZT has a strong influence on the distribution of magnetization in LSMO. The presence of polarized PZT changes the balance between the ferromagnetic and antiferromagnetic states of LSMO. The observed interfacial magnetoelectric effect can be explained by the variation of the charge density across the LSMO/PZT interface and by the change of the magnetic order in the LSMO layer adjacent to PZT.
Smart materials for sensor technology,(non) volatile device memories for information technology, ... more Smart materials for sensor technology,(non) volatile device memories for information technology, and ultrasound generators in medical imaging have one thing in common, their active elements consist of ferroelectrics (FE) driven by voltages or ferromagnetics (FM) ...
ABSTRACT There is increasing interest in modifying magnetism by electric fields for both scientif... more ABSTRACT There is increasing interest in modifying magnetism by electric fields for both scientific and technological point of view. In a ferromagnetic/piezoelectric composite structure, it is reported that the electric field can alter both the Curie temperature and the magnetization in the ferromagnetic material by inducing charge accumulation or depletion at the interface.^1 To understand the detailed changes in the magnetization profile at the interface, we performed both polarized neutron reflectivity and resonant soft X-ray reflectivity measurements on an epitaxially grown PbZr0.2Ti0.8O3(PZT)/La0.67Sr0.33MnO3 (LSMO) bilayer. A clear magneto-electric effect was observed below the Curie temperature of LSMO; i.e., the magnetization in LSMO decreases when the electric field was applied. The magnetization depth profile as a function of applied electric field will be presented.^1H. J. A. Molegraaf et al. Adv. Materials 21, 3470 (2009).^2This work is supported by DOE/BES through grant number DW-SC0003678.
ABSTRACT We employ x-ray coherent diffraction imaging to map the lattice strain distribution, ela... more ABSTRACT We employ x-ray coherent diffraction imaging to map the lattice strain distribution, elastic properties and device responses to external stimuli such as magnetic and electric field in a host of device nanostructures. For the case isolated Ni (001) nanowire grown vertically on an amorphous SiO2 /Si substrate we utilize the retrieved projection of lattice distortion to predict the Young's Modulus of the wire based on the elasticity theory [1]. We also image for the first time, the evolution of magnetostriction in these wires in the presence of an external magnetic field. For extended ferroelectric thin films, we utilized the recently developed Bragg Ptychography [2] to image the evolution of ferroelectricity [3].[4pt] [1] E. Fohtung et al., Appl. Phys. Lett. 101, 033107 (2012).[0pt] [2] S. O. Hruszkewycz et al., Nano Lett. 12, 5148 (2012).[0pt] [3] E. Fohtung et al., in preparation (2012).
We utilize polarized neutron reflectometry in consort with ab initio based density functional the... more We utilize polarized neutron reflectometry in consort with ab initio based density functional theory calculations to study interface magnetoelectric coupling across a ferroelectric PbZr0.2Ti0.8O3 and magnetic La0.67Sr0.33MnO3 heterostructure.
Lattice mismatch induced epitaxial strain has been widely used to tune functional properties in c... more Lattice mismatch induced epitaxial strain has been widely used to tune functional properties in complex oxide heterostructures. Apart from the epitaxial strain, a large lattice mismatch also produces other effects...
Journal of physics. Condensed matter : an Institute of Physics journal, Oct 5, 2016
Multiferroic heterostructures composed of thin layers of ferromagnetic and ferroelectric perovski... more Multiferroic heterostructures composed of thin layers of ferromagnetic and ferroelectric perovskites have attracted considerable attention in recent years. We apply ab initio computational methods based on density functional theory to study the magnetoelectric coupling at the (0 0 1) interface between [Formula: see text] (LSMO) and [Formula: see text] (PZT). Our study demonstrates that the ferroelectric polarization of PZT has a strong influence on the distribution of magnetization in LSMO. The presence of polarized PZT changes the balance between the ferromagnetic and antiferromagnetic states of LSMO. The observed interfacial magnetoelectric effect can be explained by the variation of the charge density across the LSMO/PZT interface and by the change of the magnetic order in the LSMO layer adjacent to PZT.
Smart materials for sensor technology,(non) volatile device memories for information technology, ... more Smart materials for sensor technology,(non) volatile device memories for information technology, and ultrasound generators in medical imaging have one thing in common, their active elements consist of ferroelectrics (FE) driven by voltages or ferromagnetics (FM) ...
ABSTRACT There is increasing interest in modifying magnetism by electric fields for both scientif... more ABSTRACT There is increasing interest in modifying magnetism by electric fields for both scientific and technological point of view. In a ferromagnetic/piezoelectric composite structure, it is reported that the electric field can alter both the Curie temperature and the magnetization in the ferromagnetic material by inducing charge accumulation or depletion at the interface.^1 To understand the detailed changes in the magnetization profile at the interface, we performed both polarized neutron reflectivity and resonant soft X-ray reflectivity measurements on an epitaxially grown PbZr0.2Ti0.8O3(PZT)/La0.67Sr0.33MnO3 (LSMO) bilayer. A clear magneto-electric effect was observed below the Curie temperature of LSMO; i.e., the magnetization in LSMO decreases when the electric field was applied. The magnetization depth profile as a function of applied electric field will be presented.^1H. J. A. Molegraaf et al. Adv. Materials 21, 3470 (2009).^2This work is supported by DOE/BES through grant number DW-SC0003678.
ABSTRACT We employ x-ray coherent diffraction imaging to map the lattice strain distribution, ela... more ABSTRACT We employ x-ray coherent diffraction imaging to map the lattice strain distribution, elastic properties and device responses to external stimuli such as magnetic and electric field in a host of device nanostructures. For the case isolated Ni (001) nanowire grown vertically on an amorphous SiO2 /Si substrate we utilize the retrieved projection of lattice distortion to predict the Young's Modulus of the wire based on the elasticity theory [1]. We also image for the first time, the evolution of magnetostriction in these wires in the presence of an external magnetic field. For extended ferroelectric thin films, we utilized the recently developed Bragg Ptychography [2] to image the evolution of ferroelectricity [3].[4pt] [1] E. Fohtung et al., Appl. Phys. Lett. 101, 033107 (2012).[0pt] [2] S. O. Hruszkewycz et al., Nano Lett. 12, 5148 (2012).[0pt] [3] E. Fohtung et al., in preparation (2012).
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Papers by Edwin Fohtung