[18p-PB1-1~73] 10 Spintronics and Magnetics (Poster)

▲ [18p-PB1-28] Voltage-controlled magnetic anisotropy in ultrathin nickel

〇Takeshi Kawabe^1,2, Risa Miyakaze¹, Takuya Tsukahara¹, Yoshinori Kotani³, Kentaro Toyoki³, Minori Goto^1,4, Tetsuya Nakamura³, Yoshishige Suzuki^1,4, Shinji Miwa^1,2,4 (1.Osaka Univ., 2.Univ. Tokyo, 3.JASRI, 4.Osaka Univ. CSRN)

Keywords:Voltage-controlled magnetic anisotropy, X-ray magnetic circular dichroism, Nickel

Voltage-controlled magnetic anisotropy (VCMA) in 3d-transition metals has been intensively studied. Recently, it has been reported that a Co/MgO, where one electron is added to 3d-orbitals of Fe, shows larger VCMA (~80 fJ/Vm) than that of Fe/MgO(~30 fJ/Vm). In this study, we have characterized the VCMA effect and the voltage-induced changes of magnetic moments in a Ni/MgO, where one electron is added to 3d-orbitals of Co.
We fabricated magnetic tunnel junction devices with Fe(0.3 nm)/Ni(0.14 nm)/MgO(1.4 nm)/Fe(10 nm) multilayer, and analyzed the VCMA effect. For the characterization of magnetic moments of Ni, a tunnel junction with an Fe(0.3 nm)/Ni(0.14 nm)/MgO(2 nm)/SiO₂(5 nm) was prepared. We measured X-ray absorption and its X-ray magnetic circular dichroism (XMCD) around Ni-L_2,3 edges at BL25SU, SPring-8. We found that bias-voltage changes the XMCD spectra, which suggests that magnetic moments of Ni were modulated by the bias-voltage.