14:30 〜 14:45
▲ [11p-Z08-8] Half-metallic Mn2RuAl/MgO (001) heterojunctions: An ab intio study
キーワード：Half-metallic, Heusler alloy, Heterojunction
In spintronics applications, materials possessing high spin polarization and high Curie temperature (TC) are highly desired. Many Co-based Heusler alloys are known to have these features. Recently we extended our research to exploration of Co-free Heusler alloys with high TC and high spin polarization at the Fermi level [1]. Based on first-principles calculations, we studied Mn2RuAl full Heusler alloy in its bulk form and its heterojunctions with MgO. Mn2RuAl crystallizes in cubic Hg2CuTi-type inverse Heusler structure. The magnetic ground state is ferrimagnetic with net magnetic moment of 1.0 μB. The Curie temperature is predicted to be 670 K within a mean-field approximation. The electronic structure is nearly half-metallic in its bulk phase.
Thereafter, we studied Mn2RuAl/MgO (001) heterojunctions for both the MnAl and MnRu terminations, in which Mn atoms are located on top of O atoms. It turns out that the MnAl-terminated interface is energetically more favorable than the MnRu-terminated one. We observed that the heterojunction remains perfectly half-metallic for the MnAl terminated case, whereas in the MnRu termination, it preserves relatively high spin polarization (82%) at the Fermi level. Note that the lattice mismatch between MgO and Mn2RuAl is only 0.25%. All these features could make Mn2RuAl a potential candidate for electrodes of MgO-based magnetic tunnel junctions (MTJs). We discuss the temperature dependence of tunneling magnetoresistance in Mn2RuAl/MgO/Mn2RuAl MTJs on the basis of the magnetic stiffness of Mn2RuAl beneath the interface with MgO. This work was in part supported by JST CREST (No. JPMJCR17J5) and CSRN, Tohoku University.
[1]Y. Onodera et al., Jpn. J. Appl. Phys., in press (https://doi.org/10.35848/1347-4065/ab9c75).
Thereafter, we studied Mn2RuAl/MgO (001) heterojunctions for both the MnAl and MnRu terminations, in which Mn atoms are located on top of O atoms. It turns out that the MnAl-terminated interface is energetically more favorable than the MnRu-terminated one. We observed that the heterojunction remains perfectly half-metallic for the MnAl terminated case, whereas in the MnRu termination, it preserves relatively high spin polarization (82%) at the Fermi level. Note that the lattice mismatch between MgO and Mn2RuAl is only 0.25%. All these features could make Mn2RuAl a potential candidate for electrodes of MgO-based magnetic tunnel junctions (MTJs). We discuss the temperature dependence of tunneling magnetoresistance in Mn2RuAl/MgO/Mn2RuAl MTJs on the basis of the magnetic stiffness of Mn2RuAl beneath the interface with MgO. This work was in part supported by JST CREST (No. JPMJCR17J5) and CSRN, Tohoku University.
[1]Y. Onodera et al., Jpn. J. Appl. Phys., in press (https://doi.org/10.35848/1347-4065/ab9c75).