The 78th JSAP Autumn Meeting, 2017

Presentation information

Oral presentation

CS Code-sharing session » 【CS.10】10.1 & 10.2 & 10.3 Code-sharing session

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

Tue. Sep 5, 2017 2:45 PM - 7:00 PM C18 (C18)

Tomohiro Nozaki(Tohoku Univ.)

5:15 PM - 5:30 PM

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

Takuya Tsukahara1, Motohiro Suzuki2, Takeshi Kawabe1, Koki Shimose1, Taishi Furuta1, Risa Miyakaze1, Kohei Nawaoka1, Minori Goto1,4, Takayuki Nozaki3, Shinji Yuasa3, Yoshinori Kotani2, Kentaro Toyoki2, Tetsuya Nakamura2, Yoshishige Suzuki1,4, Shinji Miwa1,4 (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 (Tz 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.