[22p-A205-1~18] 10.2 スピン基盤技術・萌芽的デバイス技術

▼ [22p-A205-16] Observation of persistent coherence in Y₃Fe₅O₁₂

〇Takahiko Makiuchi¹、Tomosato Hioki^2,1、Hiroki Shimizu¹、Koujiro Hoshi^1,3、Mehrdad Elyasi²、Kei Yamamoto⁴、Naoto Yokoi^1,3、Gerrit E. W. Bauer²、Eiji Saitoh^1,2,3,4 (1.Dept. Appl. Phys., UTokyo、2.AIMR, Tohoku Univ.、3.Beyond AI, UTokyo、4.JAEA)

キーワード：magnetization dynamics, spintronics, coherence

Precessional motion of magnetization around a magnetic field decays and reaches the equilibrium. It has been believed that all the information of magnetization phase coherence is lost after the damping. Here we study the phase coherence in a disk-shaped yttrium iron garnet (YIG) by using a microwave pump-and-probe method in which we obtain a measure of the phase coherence during damping. Using a parametric excitation pump pulse, we observed prolonged phase coherence after the damping, which we call persistent coherence. The time scale was two orders of magnitude longer than the damping time scale of YIG. We will discuss the measurement method and the origin of persistent coherence.