[10a-M101-1~8] 10.1 新物質・新機能創成（作製・評価技術）

▲ [10a-M101-6] Ultra-low power bias-driven magnetization switching by quasi-Fermi level control at an interface of a La_0.67Sr_0.33MnO₃-based magnetic tunnel junction

〇Anh Duc Le¹、Takashi Yamashita¹、Hiroki Yamasaki¹、Daisei Araki¹、Munetoshi Seki^1,2、Hitoshi Tabata^1,2、Masaaki Tanaka^1,2、Shinobu Ohya^1,2 (1.Tokyo Univ.、2.CSRN, Tokyo Univ.)

キーワード：magnetic anisotropy, orbital-controlled magnetization switching, Ferromagnetic oxides

Controlling the magnetic anisotropy (MA) by a bias voltage is important for reducing the power consumption of magnetization switching in spin devices. In ferromagnetic (FM) materials, the MA is strongly correlated to the symmetry of the magnetization-direction dependence of the density of states (DOS) around the Fermi level. This correlation thus suggests that we can achieve highly effective control of MA of the FM materials by applying a bias voltage and moving the Fermi level between band components with different orbital symmetries. Here in a La_0.67Sr_0.33MnO₃ (LSMO)-based magnetic tunnel junction (MTJ), we demonstrate a magnetic-field-free 90°-magnetization switching solely by applying an extremely small electric field of 0.05 V/nm on the tunnel barrier, which moves the Fermi level from the e_g band to the t_2g band at the interface between LSMO and the tunnel barrier, and induces a sharp change in the in-plane MA.The operation requires an infinitesimal current density of ~ 10^–2 A/cm², which is ~8 orders of magnitude smaller than that in the present magnetic random access memory.