[16p-D61-1~13] 10.2 スピン基盤技術・萌芽的デバイス技術

14:30 〜 14:45奨励賞エントリー英語発表

[16p-D61-6] Dynamic control of spin wave propagation by electric field in space inversion symmetry broken Iron Oxide Garnet thin films

〇(D)EMK IKBALL AHAMED¹, Md Shamim Sarker¹, Hiroyasu Yamahara¹, Haining Li¹, Siyi Tang¹, Munetoshi Seki¹, Hitoshi Tabata¹ (1.Univ. of Tokyo)

キーワード：

spin wave、tetragonal disotrtion、symmetry breaking

This study aims to control spin wave propagation in Rare-earth Iron Garnet (RIG) thin films by the electric field. Due to the existence of cubic inversion symmetry in garnets, the electromechanical and electromagnetic coupling effects are very small. To overcome this weakness, we have broken the spatial inversion symmetry by introducing a long-range strain gradient, which allows the coexistence of magnetic and electric dipole polarizations due to the tetragonal distortion. We fabricated 85 nm and 120 nm-thick Y₃Fe₅O₁₂ (YIG, 12.376Å bulk) thin films on lattice matched Ga₃Gd₅O₁₂ (GGG, 12.38Å) and ~1%lattice mismatched Gd_2.6Ca_0.4Ga_4.1Mg_0.25Zr_0.65O₁₂ (SGGG, 12.50Å) substrates by pulsed laser deposition (PLD) technique. We estimated the magnetic moments using the XMCD sum rule and found low orbital moments in YIG/GGG indicate low crystal distortion. However, large orbital momentum of 0.15 in YIG/SGGG films indicates the quenching of the orbital moment <s>s</s>um is alleviated by the reduction of crystal symmetry from cubic to tetragonal. In tensile strained YIG (120nm)/SGGG, the spin wave transmission spectra exhibit a significant rightward shift with the application of an electric field, whereas a similar investigation on lattice-matched YIG (120nm)/GGG samples subjected to a large electric field of up to 800kV/cm showed a very small response. It is expected that the SW frequency shift originated from the electrical response of the polarized domains in tensile strained RIG thin films that eventually modulates the magnetic anisotropy of insulating thin films via spin-orbit coupling. This dynamic magnon control by electric field will represent a groundbreaking advancement in magnonics, offering the potential for implementing low-power consumption logic devices through the utilization of the spin wave.