[5p-C18-8~21] 【CS.10】10.1 & 10.2 & 10.3 Code-sharing session

▼ [5p-C18-15] Voltage controlled magnetic anisotropy of monoatomic Pt layer at Fe/MgO interface characterized by X-ray absorption spectroscopy

〇Takuya Tsukahara¹, Motohiro Suzuki², Takeshi Kawabe¹, Koki Shimose¹, Taishi Furuta¹, Risa Miyakaze¹, Kohei Nawaoka¹, Minori Goto^1,4, Takayuki Nozaki³, Shinji Yuasa³, Yoshinori Kotani², Kentaro Toyoki², Tetsuya Nakamura², Yoshishige Suzuki^1,4, Shinji Miwa^1,4 (1.Osaka Univ., 2.JASRI, 3.AIST, 4.CSRN)

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

In order to control the magnetization direction in nanomagnets for magetoresistive random access memory (MRAM), voltage controlled magnetic anisotropy (VCMA) in ferromagnetic metal is a candidate. However, it is necessary to enhance VCMA for application. Recently, in L1₀-FePt/MgO system, it has been reported that voltage induction of not only orbital magnetic moment but also magnetic dipole moment (T_z term) drastically changes the magnetic anisotropy. In the present study, we report Fe/Pt/MgO system in which Pt monoatomic layer is located at the Fe/MgO interface for further investigation.
MgO(001) substrate/MgO (5 nm)/V(30 nm)/Fe(0.5 nm)/Pt (0.2 nm)/MgO(2 nm) multilayer was fabricated by molecular beam epitaxy. After that, 5 nm-SiO₂ was deposited by sputtering. Then 2 nm-Cr and 5 nm-Pd were deposited. The multilayer was patterned into tunnel junctions whose size was 80 µm in a diameter. To investigate electronic and magnetic properties of Pt, X-ray absorption spectroscopy and its X-ray magnetic circular dichroism (XMCD) were conducted at BL39XU at SPring-8. From magnetization hysteresis under external voltages of ±2.6V (±0.18 V/nm), VCMA in the system was estimated to be 140 fJ/Vm. Voltage induced lattice relaxation around Pt atom and induced XMCD change will be discussed.