[20a-D61-1~9] 10.1 新物質・新機能創成（作製・評価技術）

10:00 〜 10:15英語発表

[20a-D61-5] Large Magnetoresistance and High Spin-Transfer Torque Efficiency of Co₂Mn_xFe_1-xGe (0 ≤ x ≤ 1) Heusler Alloy Thin Films Obtained by High-Throughput Compositional Optimization Using Combinatorially Sputtered Composition-Gradient Film

〇(PC)Vineet Barwal¹, Hirofumi Suto¹, Ryo Toyama¹, Taisuke Sasaki¹, Yuya Sakuraba¹ (1.NIMS)

キーワード：

Combinatorial Sputtering、Magnetoresistance、Spin Transfer Torque Efficiency

Half-metallic ferromagnetic Heusler alloys having high spin polarization have been studied for their potential spintronic applications. For certain applications such as current-perpendicular-to-plane giant magnetoresistnace (CPP-GMR) read heads, achieving low process temperature, typically below 350°C, is crucial. Moreover, composition tuning is an important factor to enhance the properties of the Heusler systems, and we developed an experimental method for detailed high-throughput composition optimization using combinatorially sputtered composition-gradient film. In this study, we apply the developed method to Co₂Mn_xFe_1-xGe (0≤x≤1){CMFG} and report high-performance CPP-GMR properties obtained at lower process temperature.The method combined composition-gradient films and local measurements to enable the detailed composition variation from Co₂Mn_xFe_1-xGe to be studied on a single library sample and achieved the drastic increase in the throughput. Through this method, the record high MR ratio ~ 35% and 45% was achieved at relatively low annealing temperature of 250°C and 350°C, respectively. In addition, high STT efficiency ~ 0.6 was demonstrated. The results highlight the potentiality of Co₂Mn_xFe_1-xGe and provide comprehensive guidance on the composition optimization to obtain large MR ratio and high STT efficiency in the CPP-GMR devices at lower process temperature.