[11a-S302-1~11] 10.3 スピンデバイス・磁気メモリ・ストレージ技術

▲ [11a-S302-3] Theoretical analysis of parametric excitation caused by voltage control of magnetic anisotropy

〇Hiroshi Imamura¹、Rie Matsumoto¹ (1.AIST)

キーワード：MRAM, VCMA, parametric excitation

The voltage-controlled MRAM (VC-MRAM) has attracted much attention as a non-volatile memory with ultra-high speed and ultra-low power consumption. Very recently, Yamamoto et al. observed parametric excitation of magnetization precession in the VC-MRAM, which is induced by superimposing high-frequency voltage on the write pulse [T. Yamamoto et al., Nano Lett. 20, 6012 (2020)]. In this phenomenon, the oscillation of the anisotropic magnetic field generated by the high-frequency voltage efficiently assists the precessional motion of the magnetization under a certain condition. Here, we performed a detailed theoretical analysis of parametric excitation in the VC-MRAM to clarify the conditions of the high-frequency anisotropy field required for parametric excitation. The effective equations of motion for the amplitude and phase delay of the precessional motion were derived from the Landau-Lifshitz-Gilbert equation, and the excitation condition was determined by analyzing their asymptotic behavior [H. Imamura and R. Matsumoto, Phys. Rev. Appl. 14, 064062 (2020)].