Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 51: Magnetism Poster B

MA 51.52: Poster

Donnerstag, 4. April 2019, 15:00–18:00, Poster C

Theoretical analysis of electronic states at the interface between MgO and nonmagnetic metals — •Ather Ahmad, Philipp Risius, Michael Czerner, and Christian Heiliger — Institut für theoretische Physik, Justus-Liebig-Universität Gießen, Gießen

A number of nonmagnetic metals may be grown epitaxially on magnesium oxide (MgO). In combination with a ferromagnetic material, semimagnetic tunnel junctions (SMTJ) can be constructed. These tunnel junctions may show tunnelling anisotropic magnetoresistance (TAMR), where the electronic transmission varies with the magnetization direction of the ferromagnetic layer. TAMR, which exploits the spin-orbit coupling at the ferromagnet-MgO interface, is a valuable tool for examining phenomena such as spin torque [1]. To find promising combinations of materials for MgO-based SMTJs, we calculate the Bloch spectral function (BSF) at the interfaces of MgO with various nonmagnetic metals. These BSFs can be compared to the BSF at ferromagnet-MgO interfaces to predict the electronic transmission of an SMTJ combining the two materials. We show that the transmission across an SMTJ can indeed be predicted from the combination of the interfaces’ BSFs. Comparing the BSF of ferromagnet-MgO- and nonmagnet-MgO interfaces could thus help find nonmagnetic metals which provide a sizeable TAMR, enabling further studies.
 [1] S. Miwa, J. Fujimoto, P. Risius, K. Nawaoka, M. Goto, and Y. Suzuki. "Strong Bias Effect on Voltage-Driven Torque at Epitaxial Fe-MgO Interface". Physical Review X 7(3), 031018 (2017).