[19a-331-7~12] 10.3 Spin devices, magnetic memories and storages

▼ [19a-331-11] Origin of bi-quadratic interlayer exchange coupling in Co₂MnSi-based pseudo spin valves

〇(M2)Daiki Mouri¹, Masaki Inoue¹, Kazuumi Inubushi², Tessei Tanimoto¹, Katsuyuki Nakada², Masafumi Yamamoto¹, Tetsuya Uemura¹ (1.Hokkaido Univ., 2.TDK Corp.)

Keywords:GMR, Heusler alloys, Interlayer exchange coupling

We fabricated current-perpendicular-to-plane pseudo spin valves (CPP-PSVs) having Co₂MnSi electrodes with various Mn compositions, α, and an Ag spacer, and investigated the strength of bi-quadratic interlayer exchange coupling (90° coupling) in the CPP-PSVs by comparing magnetoresistance characteristics and spin-transfer-torque induced magnetization switching characteristics. We experimentally found that (a) the strength of 90° coupling increased as α increased, (b) it was weakened by insertion of CoFe between CMS and the Ag spacer, resulting in the suppression of the 90° coupling at 290 K, and (c) it strongly depended on temperature. These results can be understood by the interpretation that loosely coupled spins due to Mn atoms diffused into an Ag spacer are the origin of 90° coupling.