Ballistic spin-transport properties of magnetic tunnel junctions with MnCr-based ferrimagnetic quaternary Heusler alloys

被引：1

作者：

Roy T. ^{[1
]}

Tsujikawa M. ^{[2
]}

Shirai M. ^{[1
,2
]}

机构：

[1] Center for Science and Innovation in Spintronics, Core Research Cluster, Tohoku University, Sendai

[2] Research Institute of Electrical Communication, Tohoku University, Sendai

来源：

Physical Review Materials | 2023年 / 7卷 / 10期

基金：

日本科学技术振兴机构;

关键词：

Compendex;

D O I：

10.1103/PhysRevMaterials.7.104410

中图分类号：

学科分类号：

摘要：

We investigate the suitability of nearly half-metallic ferrimagnetic quaternary Heusler alloys, CoCrMnZ (Z = Al, Ga, Si, Ge), to assess their feasibility as electrode materials for MgO-based magnetic tunnel junctions (MTJs). The low magnetic moments of these alloys originating from the antiferromagnetic coupling between Mn and Cr spins ensure a negligible stray field in spintronics devices as well as a lower switching current required to flip their spin direction. We confirmed the mechanical stability of these materials with the evaluated values of elastic constants and by the absence of any imaginary frequency in their phonon dispersion curves. The influence of swapping disorders on the electronic structures and their relative stability is also discussed. High spin polarization of the conduction electrons is observed in the case of CoCrMnZ/MgO heterojunctions, independent of terminations at the interface. Based on our ballistic transport calculations, large coherent tunneling of the majority-spin s-like Δ1 states can be expected through the MgO barrier. The calculated tunneling magnetoresistance (TMR) ratios are on the order of 1000%. Very high Curie temperatures specifically for CoCrMnAl and CoCrMnGa, which are comparable to bcc Co, could also yield a weaker temperature dependence of TMR ratios for CoCrMnAl/MgO/CoCrMnAl (001) and CoCrMnGa/MgO/CoCrMnGa (001) MTJs. © 2023 American Physical Society.

引用