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▲ [19p-P1-53] Magnetic properties and lateral spin-valve device application of MnAs/InAs/GaAs(111)B
Keywords:III-V semiconductor,Magnetization,Spin valve device
Ferromagnetic-semiconductor hybrid structures have already attracted attention for spintronic applications, such as spin-field effect transistors (spin-FETs) [1]. We reported molecular beam epitaxial (MBE) growth of a ferromagnetic-semiconductor hybrid structure, MnAs/InAs/GaAs(111)B, and its basic electrical properties [2]. We confirmed hexagonal MnAs having [0001] and [-2110] parallel to [-1-1-1] and [-110] of InAs/GaAs, and good Ohmic behavior having specific contact resistance of 6.4x10-5 Ωcm2 through MnAs/InAs interface. In this report, we focus on magnetic properties and lateral spin-valve device application of the hybrid structure.
The thicknesses of MnAs and InAs are ~200 and ~1200 nm, respectively. For magnetic property characterization, we used a superconducting quantum interference device (SQUID) magnetometer. For lateral spin-valve device fabrication, we used electron-beam lithography (EBL), Ar+ or wet-chemical etching. For the device measurements, we performed non-local measurements with DC current.
Figure 1 shows magnetization curves of as-grown hybrid structure at room temperature for 3 applying magnetic field (H) directions. In the case of out-of-plane H, the magnetization seems hard and the hysteresis loop is small. In the cases of in-plane H, the magnetization seems easy and clear hysteresis loops can be observed. The saturation magnetization is almost similar to reported value [3], however, no significant in-plane anisotropy is observed at present unlike ref. [3]. Figure 2 shows non-local spin-valve signal curves in MnAs electrode spacing of 1 µm at room temperature. The signal does not seem so clear, however, spin-valve like dips with hysteresis can be found around +25 and -15 mT. We also checked electrode spacing dependence and roughly obtained the spin diffusion length of ~0.7 µm. However, we note that there are some problems in device fabrication like etchant penetration and in data reliability like asymmetric behavior of spin-valve signal curves to zero magnetic field.
[1] S. Datta and B. Das, Appl. Phys. Lett. 56 (1990) 665. [2] C. T. Nguyen et. al., 62nd JSAP spring meeting (2015) 13a-P15-5. [3] M.Tanaka et. al., J. Appl. Phys. 76 (1994) 6278.
The thicknesses of MnAs and InAs are ~200 and ~1200 nm, respectively. For magnetic property characterization, we used a superconducting quantum interference device (SQUID) magnetometer. For lateral spin-valve device fabrication, we used electron-beam lithography (EBL), Ar+ or wet-chemical etching. For the device measurements, we performed non-local measurements with DC current.
Figure 1 shows magnetization curves of as-grown hybrid structure at room temperature for 3 applying magnetic field (H) directions. In the case of out-of-plane H, the magnetization seems hard and the hysteresis loop is small. In the cases of in-plane H, the magnetization seems easy and clear hysteresis loops can be observed. The saturation magnetization is almost similar to reported value [3], however, no significant in-plane anisotropy is observed at present unlike ref. [3]. Figure 2 shows non-local spin-valve signal curves in MnAs electrode spacing of 1 µm at room temperature. The signal does not seem so clear, however, spin-valve like dips with hysteresis can be found around +25 and -15 mT. We also checked electrode spacing dependence and roughly obtained the spin diffusion length of ~0.7 µm. However, we note that there are some problems in device fabrication like etchant penetration and in data reliability like asymmetric behavior of spin-valve signal curves to zero magnetic field.
[1] S. Datta and B. Das, Appl. Phys. Lett. 56 (1990) 665. [2] C. T. Nguyen et. al., 62nd JSAP spring meeting (2015) 13a-P15-5. [3] M.Tanaka et. al., J. Appl. Phys. 76 (1994) 6278.