Abstract：One of the most important in spintronics is magnetization switching using spin polarized current, in which the spin orbit torque based on strong spin orbit coupling is an effective method. The recent progress of spin orbit torque in MnGa/heavy metals and MnAl/heavy metals heterojunctions were briefly described. Firstly, the physical origin of spin orbit torque were reviewed, and then how to decrease the applied magnetic field and increase the efficiency of spin orbit torque were discussed. Finally, the prospects for the development of spin orbit torque in these heterojunctions were presented.
[1] Miron, I M, et al. Perpendicular switching of a single ferromagnetic layer induced by in-plane current injection [J]. Nature, 2011, 476, 189-193. [2] Liu L, et al. Spin-torque switching with the giant spin Hall effect of tantalum [J]. Science, 2012, 336, 555-558. [3] Liu, L, et al. Current-induced switching of perpendicularly magnetized magnetic layers using spin torque from the spin Hall effect [J]. Physical Review Letters, 2012, 109, 096602. [4] Pai, C –F, et al. Spin transfer torque devices utilizing the giant spin Hall effect of tungsten [J]. Applied Physics Letters, 2012, 101, 122404. [6] Lee, K –S, et al. Threshold current for switching of a perpendicular magnetic layer induced by spin Hall effect [J]. Applied Physics Letters, 2013, 102, 112410. [7] Garello, K, et al. Symmetry and magnitude of spin–orbit torques in ferromagnetic heterostructures [J]. Nature Nanotechnology, 2013, 8, 587-593. [8] Pai, C –F, et al. Enhancement of perpendicular magnetic anisotropy and transmission of spin-Hall-effect-induced spin currents by a Hf spacer layer in W/Hf/CoFeB/MgO layer structures [J]. Applied Physics Letters, 2014, 104, 082407. [9] Fan, Y, et al. Magnetization switching through giant spin-orbit torque in a magnetically doped topological insulator heterostructure [J]. Nature Materials, 2014, 13, 699-704.[10] Yu, G, et al. Switching of perpendicular magnetization by spin-orbit torques in the absence of external magnetic fields [J]. Nature Nanotechnology, 2014, 9, 548-554. [11] Garello, K, et al. Ultrafast magnetization switching by spin–orbit torques [J]. Applied Physics Letters, 2014, 105, 212402. [12] Akyol, M, et al. Current-induced spin-orbit torque switching of perpendicularly magnetized Hf/CoFeB/MgO and Hf/CoFeB/TaOx structures [J]. Applied Physics Letters, 2015, 106, 162409. [13] Avci, C O, et al. Fieldlike and antidaming spin-orbit torques in as-grown and annealed Ta/CoFeB/MgO layers [J]. Physical Review B, 2014, 89, 214419. [14] Hayashi, M, et al. Quantitative characterization of the spin-orbit torque using harmonic Hall voltage measurements [J]. Physical Review B, 2014, 89, 144425. [16] Meng, K K, et al. Anomalous Hall effect and spin-orbit torques in MnGa/IrMn films: Modification from strong spin Hall effect of the antiferromagnet [J]. Physical Review B, 2016, 94, 214413. [17] Meng, K K, et al. Enhanced spin-orbit torques in MnAl/Ta films with improving chemical ordering [J]. Applied Physics Letters, 2017, 110, 142401.
2018, Vol. 25 
