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Front. Chem. | doi: 10.3389/fchem.2019.00550

Extremely large non-equilibrium tunnel magnetoresistance ratio in CoRhMnGe based magnetic tunnel junction by interface modification

Yu Feng1, Z.X. Cheng2* and  Xiaotian WANG3*
  • 1Jiangsu Normal University, China
  • 2University of Wollongong, Australia
  • 3Southwest University, China

Equiatomic quaternary Heusler compounds (EQHCs) generally have advantages of high Curie temperature, large spin polarization and long spin diffusion length, and they are regarded as one of the most promising candidates for spintronics devices. Herein, we report a theoretical investigation on an EQHC CoRhMnGe based magnetic tunnel junction (MTJ) with (i) MnGe-terminated interface and (ii) modified pure Mn terminated interface, i.e., MnMn-terminated interface. By employing first principles calculations combine with nonequilibrium Green’s function, the local density of states (LDOS), transmission coefficient, spin-polarized current, tunnel magnetoresistance (TMR) ratio and spin injection efficiency (SIE) as a function of bias voltage are studied. It reveals that when the MTJ under equilibrium state, TMR ratio of MnGe-terminated structure is as high as 3438%. When the MTJ is modified to MnMn-terminated interface, TMR ratio at equilibrium is enhanced to 2×105%, and spin filtering effect also get strengthened. When bias voltage is applied to the MTJ, the TMR ratio of the MnGe-terminated structure suffers dramatically loss. While the modified MnMn-terminated structure could preserve a large TMR value of 1×105% even bias voltage rises up to 0.1V, showing a robust bias endurance. These excellent spin transport properties make the CoRhMnGe a promising candidate material for spintronics device.

Keywords: interface, Magnetic tunnel junction, non-equilibrium Green’ function, first-principles calculation, Heusler

Received: 18 Jun 2019; Accepted: 19 Jul 2019.

Edited by:

Adlane Sayede, Artois University, France

Reviewed by:

Rabah Khenata, Faculty of Science and Technology, University of Mascara, Algeria
Yanxue Chen, Shandong University, China  

Copyright: © 2019 Feng, Cheng and WANG. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Prof. Z.X. Cheng, University of Wollongong, Wollongong, 2522, New South Wales, Australia, cheng@uow.edu.au
Prof. Xiaotian WANG, Southwest University, Chongqing, China, xiaotianwang@swu.edu.cn