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Full-Text Articles in Physics

Electrically Reversible Magnetization At The Antiperovskite/Perovskite Interface, Ding-Fu Shao, Gautam Gurung, Tula R. Paudel, Evgeny Y. Tsymbal Feb 2019

Electrically Reversible Magnetization At The Antiperovskite/Perovskite Interface, Ding-Fu Shao, Gautam Gurung, Tula R. Paudel, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Using density-functional calculations, we predict the emergence of electrically reversible magnetization at the interface between antiferromagnetic noncollinear antiperovskite GaNMn3 and ferroelectric perovskite BaTiO3. We find that Mn magnetic moments are enhanced and reoriented at the GaNMn3/ATiO3 (001) (A = Sr and Ba) interface, resulting in a sizable net magnetization along the [110] direction. This magnetization is reversed with ferroelectric polarization of BaTiO3 through ∼20◦ rotation of the noncollinear magnetic moments. The effect is driven by ferroelectric modulation of the antiferromagnetic exchange coupling between the interfacial Mn atoms mediated by the Mn-3d orbital population. Our results open opportunities for controlling the ...


Tunneling Anisotropic Magnetoresistance In A Magnetic Tunnel Junction With Half-Metallic Electrodes, John D. Burton, Evgeny Y. Tsymbal Jan 2016

Tunneling Anisotropic Magnetoresistance In A Magnetic Tunnel Junction With Half-Metallic Electrodes, John D. Burton, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Tunneling anisotropic magnetoresistance (TAMR) is the difference in resistance of a magnetic tunnel junction due to a change in magnetization direction of one or both magnetic electrodes with respect to the flow of current. We present the results of first-principles density functional calculations of the TAMR effect in magnetic tunnel junctions with La0.7Sr0.3MnO3 (LSMO) electrodes and a SrTiO3 (STO) tunneling barrier. We find an ∼500% difference in resistance between magnetization in the plane and out of the plane. This large TAMR effect originates from the half-metallic nature of LSMO: When magnetization is ...


Electric Control Of Spin Injection Into A Ferroelectric Semiconductor, Xiaohui Liu, John D. Burton, M. Ye. Zhuravlev, Evgeny Y. Tsymbal Jan 2015

Electric Control Of Spin Injection Into A Ferroelectric Semiconductor, Xiaohui Liu, John D. Burton, M. Ye. Zhuravlev, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Electric-field control of spin-dependent properties has become one of the most attractive phenomena in modern materials research due to the promise of new device functionalities. One of the paradigms in this approach is to electrically toggle the spin polarization of carriers injected into a semiconductor using ferroelectric polarization as a control parameter. Using first-principles density-functional calculations, we explore the effect of ferroelectric polarization of electron-doped BaTiO3 (n-BaTiO3) on the spin-polarized transmission across the SrRuO3/n-BaTiO3(001) interface. Our study reveals that, in this system, the interface transmission is negatively spin polarized and that ferroelectric ...


Ferroelectric Polarization Dependent Interface Effects, Xiaohui Liu Dec 2014

Ferroelectric Polarization Dependent Interface Effects, Xiaohui Liu

Theses, Dissertations, and Student Research: Department of Physics and Astronomy

Utilization of the switchable spontaneous polarization of nanometer scale ferroelectric materials offers a promising avenue for future nanoelectronic devices. In this dissertation, we use density-functional calculations and phenomenological modeling to explore the effects of interface termination on thin-film heterostructures, the effects of electron doping in bulk ferroelectric materials on ferroelectric stability, and the effects of ferroelectric polarization switching on the electronic and transport properties of interfaces.

For SrRuO3/BaTiO3/SrRuO3 epitaxial heterostructures grown on SrTiO3, we find that the built-in dipole at the BaO/RuO2 terminated interface leads to a strong preference for one polarization ...


Ferroelectric Tunnel Junctions With Graphene Electrodes, Haidong Lu, Alexey Lipatov, Sangjin Ryu, D. J. Kim, H. Lee, M. Ye. Zhuravlev, Chang-Beom Eom, Evgeny Y. Tsymbal, Alexander Sinitskii, Alexei Gruverman Nov 2014

Ferroelectric Tunnel Junctions With Graphene Electrodes, Haidong Lu, Alexey Lipatov, Sangjin Ryu, D. J. Kim, H. Lee, M. Ye. Zhuravlev, Chang-Beom Eom, Evgeny Y. Tsymbal, Alexander Sinitskii, Alexei Gruverman

Evgeny Tsymbal Publications

Polarization-driven resistive switching in ferroelectric tunnel junctions (FTJs)—structures composed of two electrodes separated by an ultrathin ferroelectric barrier—offers new physics and materials functionalities, as well as exciting opportunities for the next generation of non-volatile memories and logic devices. Performance of FTJs is highly sensitive to the electrical boundary conditions, which can be controlled by electrode material and/or interface engineering. Here, we demonstrate the use of graphene as electrodes in FTJs that allows control of interface properties for significant enhancement of device performance. Ferroelectric polarization stability and resistive switching are strongly affected by a molecular layer at the ...


Interface Effects In Spin-Dependent Tunneling, Evgeny Y. Tsymbal, Kirill D. Belashchenko, Julian P. Velev, Sitaram Jaswal, Mark Van Schilfgaarde, Ivan I. Oleynik, Derek A. Stewart Feb 2007

Interface Effects In Spin-Dependent Tunneling, Evgeny Y. Tsymbal, Kirill D. Belashchenko, Julian P. Velev, Sitaram Jaswal, Mark Van Schilfgaarde, Ivan I. Oleynik, Derek A. Stewart

Evgeny Tsymbal Publications

In the past few years the phenomenon of spin dependent tunneling (SDT) in magnetic tunnel junctions (MTJs) has aroused enormous interest and has developed into a vigorous field of research. The large tunneling magnetoresistance (TMR) observed in MTJs garnered much attention due to possible application in random access memories and magnetic field sensors. This led to a number of fundamental questions regarding the phenomenon of SDT. One such question is the role of interfaces in MTJs and their effect on the spin polarization of the tunneling current and TMR. In this paper we consider different models which suggest that the ...