Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 7 of 7

Full-Text Articles in Physics

Space-Charge Limited Conduction In Epitaxial Chromia Films Grown On Elemental And Oxide-Based Metallic Substrates, C.-P. Kwan, Mike Street, Ather Mahmood, Will Echtenkamp, M. Randle, K. He, J. Nathawat, N. Arabchigavkani, B. Barut, S. Yin, R. Dixit, Uttam Singisetti, Christian Binek, J. P. Bird May 2019

Space-Charge Limited Conduction In Epitaxial Chromia Films Grown On Elemental And Oxide-Based Metallic Substrates, C.-P. Kwan, Mike Street, Ather Mahmood, Will Echtenkamp, M. Randle, K. He, J. Nathawat, N. Arabchigavkani, B. Barut, S. Yin, R. Dixit, Uttam Singisetti, Christian Binek, J. P. Bird

Christian Binek Publications

We study temperature dependent (200 – 400 K) dielectric current leakage in high-quality, epitaxial chromia films, synthesized on various conductive substrates (Pd, Pt and V2O3). We find that trap-assisted space-charge limited conduction is the dominant source of electrical leakage in the films, and that the density and distribution of charge traps within them is strongly dependent upon the choice of the underlying substrate. Pd-based chromia is found to exhibit leakage consistent with the presence of deep, discrete traps, a characteristic that is related to the known properties of twinning defects in the material. The Pt- and V2O3-based films, in contrast, show ...


Dirac Nodal Line Metal For Topological Antiferromagnetic Spintronics, Ding-Fu Shao, Gautam Gurung, Shu-Hui Zhang, Evgeny Y. Tsymbal Feb 2019

Dirac Nodal Line Metal For Topological Antiferromagnetic Spintronics, Ding-Fu Shao, Gautam Gurung, Shu-Hui Zhang, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Topological antiferromagnetic (AFM) spintronics is an emerging field of research, which exploits the N´eel vector to control the topological electronic states and the associated spin-dependent transport properties. A recently discovered N´eel spin-orbit torque has been proposed to electrically manipulate Dirac band crossings in antiferromagnets; however, a reliable AFM material to realize these properties in practice is missing. In this Letter, we predict that room-temperature AFM metal MnPd2 allows the electrical control of the Dirac nodal line by the N´eel spin-orbit torque. Based on first-principles density functional theory calculations, we show that reorientation of the N´eel ...


Persistent Spin Texture Enforced By Symmetry, L. L. Tao, Evgeny Y. Tsymbal Jul 2018

Persistent Spin Texture Enforced By Symmetry, L. L. Tao, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Persistent spin texture (PST) is the property of some materials to maintain a uniform spin configuration in the momentum space. This property has been predicted to support an extraordinarily long spin lifetime of carriers promising for spintronics applications. Here, we predict that there exists a class of noncentrosymmetric bulk materials, where the PST is enforced by the nonsymmorphic space group symmetry of the crystal. Around certain high symmetry points in the Brillouin zone, the sublattice degrees of freedom impose a constraint on the effective spin–orbit field, which orientation remains independent of the momentum and thus maintains the PST. We ...


Proximitized Materials, Igor Žutić, Alex Matos-Abiague, Benedikt Scharf, Hanan Dery, Kirill Belashchenko May 2018

Proximitized Materials, Igor Žutić, Alex Matos-Abiague, Benedikt Scharf, Hanan Dery, Kirill Belashchenko

Faculty Publications, Department of Physics and Astronomy

Advances in scaling down heterostructures and having an improved interface quality together with atomically thin two-dimensional materials suggest a novel approach to systematically design materials. A given material can be transformed through proximity effects whereby it acquires properties of its neighbors, for example, becoming superconducting, magnetic, topologically nontrivial, or with an enhanced spin-orbit coupling. Such proximity effects not only complement the conventional methods of designing materials by doping or functionalization but can also overcome their various limitations. In proximitized materials it is possible to realize properties that are not present in any constituent region of the considered heterostructure. While the ...


Novel Half-Metallic And Spin-Gapless Heusler Compounds, Yunlong Jin Aug 2017

Novel Half-Metallic And Spin-Gapless Heusler Compounds, Yunlong Jin

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

This thesis is devoted to experimental studies of Heusler compounds CoFeCrAl, CoFeCrX (X = Si, Ge) and Mn2PtSn. These Heusler alloys present an interesting class of ferromagnetic materials for spintronic applications since they are predicted to be spin gapless semiconductors and have half-metallic properties with 100 % spin polarization at the Fermi level. In this thesis, the structural, magnetic, spin-polarization and electron- transport properties of the fabricated alloys were studied. CoFeCrAl thin films deposited on MgO exhibit nearly perfect epitaxy and a high degree of L21 Heusler order. All considered types of chemical disorder destroy the spin-gapless semiconductivity of ...


Interface States In Cofe2o4 Spin-Filter Tunnel Junctions, Pavel V. Lukashev, John D. Burton, Alexander Smogunov, Julian P. Velev, Evgeny Y. Tsymbal Oct 2013

Interface States In Cofe2o4 Spin-Filter Tunnel Junctions, Pavel V. Lukashev, John D. Burton, Alexander Smogunov, Julian P. Velev, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Spin-filter tunneling is a promising way to generate highly spin-polarized current, a key component for spintronics applications. In this paper we explore the tunneling conductance across the spin-filter material CoFe2O4 interfaced with Au electrodes, a geometry which provides nearly perfect lattice matching at the CoFe2O4/Au(001) interface. Using density functional theory calculations we demonstrate that interface states play a decisive role in controlling the transport spin polarization in this tunnel junction. For a realistic CoFe2O4 barrier thickness, we predict a tunneling spin polarization of about −60%. We show that this ...


Piezomagnetism In Epitaxial Cr2o3 Thin Films And Spintronic Applications, Sarbeswar Sahoo, Christian Binek Mar 2007

Piezomagnetism In Epitaxial Cr2o3 Thin Films And Spintronic Applications, Sarbeswar Sahoo, Christian Binek

Christian Binek Publications

Stress-induced perturbation of the antiferromagnetic long-range order in epitaxially grown Cr2O3 thin films gives rise to pronounced piezomagnetism and a significant reduction of the antiferromagnetic ordering temperature. The temperature dependence of the piezomagnetic moment measured by superconducting quantum interference device magnetometry reveals a power law behaviour with a critical exponent 2B=0.66 in accordance with the Ising anisotropy of a three-dimensional system. The observed shift of the Neel temperature allows estimating the internal lateral stress which is in excellent agreement with an independent estimate based on the elastic properties of Cr2O3 and the lattice mismatch at the interface between ...