Engineering spin-orbit torque in Co/Pt multilayers with perpendicular magnetic anisotropy

Abstract

To address thermal stability issues for spintronic devices with a reduced size, we investigate spin-orbit torque in Co/Pt multilayers with strong perpendicular magnetic anisotropy. Note that the spin-orbit torque arises from the global imbalance of the spin currents from the top and bottom interfaces for each Co layer.By inserting Ta or Cu layers to strengthen the top-down asymmetry, the spin-orbit torque efficiency can be greatly modified without compromised perpendicular magnetic anisotropy. Above all, the efficiency builds up as the number of layers increases, realizing robust thermal stability and high spin-orbit-torque efficiency simultaneously in the multilayers structure.

Strong Electrical Manipulation of Spin–Orbit Torque in Ferromagnetic Heterostructures

“…and/or the Rashba effect from the inversion asymmetry of HM/FM and FM/oxide interfaces both contribute to the spin-orbit torque and the effective switching fi eld. [21][22][23][24] At the same time, electric fi eld control of magnetization is of great interest in the area of spintronics for its rich physics and potential use in information technology due to its low energy consumption and compatibility with classic electronics. [ 20 ] Efforts are increasingly shifting not only to explore SOT in different systems, but also to its manipulation in practical devices.…”

Helicity and field dependent magnetization dynamics of ferromagnetic Co/Pt multilayers

“…Attempts of engineering new materials suitable for both AOS and technological applications 2 resulted in the surprising observation of a helicity-dependent all-optical magnetization reversal 3 in a number of ferromagnetic multilayers with a perpendicular magnetic anisotropy. [4][5][6] This effect was particularly found in Co/X (¼Pt, Pd,…) multilayers, a class of materials known for their strong thermal stability 7 and their potential for patterned magnetic media 8,9 or spin-transfer torque based memory [10][11][12][13] applications. The enhanced spin-orbit coupling at the Co/Pt or Co/Pd interfaces was shown to cause an increased rate of laser-induced demagnetization 18 compared to that of pure transition metal thin films.…”

Temperature dependence of spin-orbit torques across the magnetic compensation point in a ferrimagnetic TbCo alloy film

“…SOTs have been identified and quantified by a variety of techniques including spin-torque ferromagnetic resonance [2,7,14,17,19,25], quasistatic magnetization tilting probed through harmonic voltage measurements [6,[8][9][10][11][12][13]17,[19][20][21][22][23][24][25][26]28,31], and current-induced hysteresis loop shift measurements [18,32,33]. Most studies of SOTs have focused on ultrathin metallic ferromagnet/heavy-metal bilayers with interfacial perpendicular magnetic anisotropy (PMA) [1][2][3][5][6][7][8][9][11][12][13][15][16][17][18][19][20][21][22][23][24][25]…”