講演情報
[15p-P07-58]All-Optical Magnetization Switching in Ferromagnet-Ferrimagnet Coupled Films with Perpendicular Magnetic Anisotropy
〇Luding WANG1,2, Soma Miki2,3, Satoshi Iihama4, Kazuaki Ishibashi5,2, Kouki Nukui5,2, Deepak Kumar2, Mio Ishibashi2, Hiroki Morishita1,2, Shigemi Mizukami2,1 (1.CSIS, Tohoku Univ., 2.WPI-AIMR, Tohoku Univ., 3.Osaka Univ., 4.Dept. of Mater. Phys., Nagoya Univ., 5.Grad. Sch. Eng., Tohoku Univ.)
キーワード：
spintronics、magneto-optics
All-optical switching (AOS) of magnetization presents a promising pathway for realizing opto-spintronic applications. Recent studies highlight the potential of integrating AOS with magnetic tunnel junctions (MTJs) for optically-accessible MRAM, in which the data is recorded via AOS in ferrimagnets [1-4]. However, to realize practical memory application, enhanced device performance including tunnel magnetoresistance for data reading, as well as high magnetic anisotropy for data retention, are required. Here, we investigated AOS in ferromagnetic-ferrimagnetic coupled nanostructure MgO(2)/CoFeB(1.2)/Ta(0.6)/Co(1)/Gd(3)/Pt(2) deposited on Si/SiO2 substrates via a magnetron sputtering [4], where the 0.6-nm-thick Ta spacer is used for the interlayer exchange coupling in the present study. Figure 1 shows the polar magneto-optical Kerr effect (MOKE) loop of the stack at different annealing temperatures. Decent perpendicular magnetic anisotropy (PMA) is achieved at annealing 200°C and 300°C, compatible with MTJ process. Using femtosecond laser pulses, we investigated AOS via Kerr microscopy, as shown in Fig. 2. A signature of complete magnetization reversal under zero magnetic field at a laser fluence of 1.7 mJ/cm2 is clearly shown. We will present the detailed experimental data in the presentation. This work was supported by KAKENHI (24K21234, 21H05000), MEXT X-NICS (JPJ011438), and Spin-RNJ. K.N and K.I thank to the GP-Spin at Tohoku Univ. K.I thanks to the JSPS fellow.