Time dependence of magnetization reversal influenced by current in perpendicularly magnetized Co/Pt thin film

Abstract

We have investigated thermally activated magnetization reversal influenced by the current in a Co/Pt thin film with perpendicular magnetic anisotropy at room temperature by measuring the extraordinary Hall effect. The magnetization could reverse in a fixed magnetic field lower than the coercive field as increasing the current, which depends on the current-sweep rate. The characteristic current for zero net magnetization is small for a low current-sweep rate and a high fixed field. Magnetization reversal becomes fast for a high current-sweep rate and a high fixed field. With the constant current, the magnetization reversal is fast for a large current and a high fixed field. The magnitude of the propagation field HP∗ reduces more than 70 Oe when the current density J reaches 1.25×105 A/cm2, which is mainly on account of the sample temperature rise due to current-induced Joule heating. Also, the effective field HI associated with spin transfer and momentum transfer perhaps has a contribution to magnetization reversal through thermal activation in a multidomain macroscopic thin film. The results show that the Joule heating and current associated effective field can reduce the activation energy barriers and speed up magnetization reversal besides the applied magnetic field.

Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems

“…This observation was soon confirmed by several groups using different magnetic stacks and heavy metal substrates (Avci et al, 2012(Avci et al, , 2014bEmori et al, 2013;Pai et al, 2012;Yu et al, 2014b), as well as antiferromagnets (Fukami et al, 2016b;Oh et al, 2016;Wadley et al, 2016), magnetic insulators (Avci et al, 2017a;Li et al, 2016b), and topological insulators (Han et al, 2017;Mahendra et al, 2018;Wang et al, 2017b). Notably, earlier investigations of Pt/Co/Pt and Pt/Co also reported an effect of very small current densities on the low temperature coercivity of Co, albeit mainly attributed to Joule heating (Lin et al, 2006;Riss et al, 2010;Xie et al, 2008).…”

Current-induced domain wall motion in Co/Pt nanowires: Separating spin torque and Oersted-field effects

“…[3][4][5][6][7] Recent studies on materials with perpendicular anisotropy have revealed a higher efficiency for CIDM than in the case of in-plane magnetized materials. [8][9][10][11] Especially the contributions of the adiabatic 12,13 and nonadiabatic spin torque due to spin relaxation [14][15][16] or momentum transfer 12,14 to the domain wall ͑DW͒ motion and their dependence on the material properties are so far not fully understood. In particular, studies on Co/Pt multilayers show a large nonadiabaticity factor ␤.…”

Switching of Perpendicular Magnetization by Spin–Orbit Torque

“…The latter includes the bulk spin Hall effect (SHE), [28][29][30][31] topological surface states, [32,33] interfacial SOC effects, [34][35][36][37][38] orbit-spin conversion, [39] the anomalous Hall effect, [40] the planar Hall effect, [41,42] the magnetic SHE, [41][42][43][44][45] Dresselhaus effect, [46] etc. The bulk SHE has been widely observed in thin-film heavy metal (HM), [4][5][6][7][8][9][10][11][12][47][48][49] Bi-Sb, [50] Bi x Te 1−x , [51] CoPt, [52] FePt, [53] Fe x Tb 1−x , [54] and Co-Ni-B. [55] Generation of transverse spins by the SHE can be highly efficient as indicated by the giant interfacial damping-like SOT efficiency of ≥0.25.…”

“…Since the discovery that an in-plane charge current in certain heavy metal thin films can be utilized to manipulate and excite the magnetization state of an adjacent ferromagnetic layer, [2][3][4][5][6][7][8][9] spin-orbit torques (SOTs) have become a powerful and versatile tool to manipulate magnetic materials. SOTs are exerted when angular momentum is transferred from a spin current or spin accumulation.…”