Ab initio study of electronic and magnetic properties of Mn2Ru Z/MgO (001) heterojunctions (Z= Al, Ge)

Tufan Roy; Masahito Tsujikawa; Masafumi Shirai

doi:10.1088/1361-648X/abdffc

Ab initio study of electronic and magnetic properties of Mn₂Ru Z/MgO (001) heterojunctions (Z= Al, Ge)

J Phys Condens Matter. 2021 Feb 18;33(14). doi: 10.1088/1361-648X/abdffc.

Authors

Tufan Roy¹, Masahito Tsujikawa^{1

2}, Masafumi Shirai^{1

2

3}

Affiliations

¹ Research Institute of Electrical Communication (RIEC), Tohoku University, Sendai 980-8577, Japan.
² Center for Spintronics Research Network (CSRN), Tohoku University, Sendai 980-8577, Japan.
³ Center for Science and Innovation in Spintronics (CSIS), Core Research Cluster (CRC), Tohoku University, Sendai 980-8577, Japan.

PMID: 33498024
DOI: 10.1088/1361-648X/abdffc

Abstract

We studied the applicability of Heusler alloys Mn₂RuZ(Z= Al, Ga, Ge, Si) to the electrode materials of MgO-based magnetic tunnel junctions. All these alloys possess Hg₂CuTi-type inverse Heusler alloy structure and ferrimagnetic ground state. Our study reveals the half-metallic electronic structure with highly spin-polarized Δ₁band, which is robust against atomic disorder. Next we studied the electronic structure of Mn₂RuAl/MgO and Mn₂RuGe/MgO heterojunctions. We found that the MnAl- or MnGe-terminated interface is energetically more favorable compared to the MnRu-terminated interface. Interfacial states appear at the Fermi level in the minority-spin gap for the Mn₂RuGe/MgO junction. We discuss the origin of these interfacial states in terms of local environment around each constituent atom. On the other hand, in the Mn₂RuAl/MgO junction, high spin polarization of bulk Mn₂RuAl is preserved independent of its termination.

Keywords: Heusler alloy; ab initio study; heterojunctions; spintronics.