[20p-B101-1~12] 10.3 スピンデバイス・磁気メモリ・ストレージ技術

▲ [20p-B101-2] Evaluation of spin-transfer-torque efficiency of FeCr with negative spin polarization using magnetization reversal against a magnetic field

〇Hirofumi Suto¹、Nakatani Tomoya¹、Asam Nagarjuna¹、Iwasaki Hitoshi¹、Sakuraba Yuya¹ (1.NIMS)

キーワード：Spin-transfer torque, FeCr, Negative spin polarization

FeCr attracts attention as a magnetic material with negative spin polarization. Such materials can increase the freedom in the designs of spintronics devices because they generate STT of the desired spin direction, where a standard positive spin polarization material works oppositely. We propose an experimental method to directly evaluate STT efficiency, in which the magnetization is reversed against a magnetic field by STT, and we apply this technique to investigate the negative spin polarization of FeCr. The bias current amplitude necessary for the magnetization reversal increases linearly with the perpendicular magnetic field, and the STT efficiency can be estimated from the slope of the field dependence. By this method, the STT efficiency of FeCr was estimated to be approximately half of that of NiFe.