Current induced chiral domain wall motion in CuIr/CoFeB/MgO thin films with strong higher order spin–orbit torques

Abstract

We investigate the Dzyaloshinskii–Moriya interaction (DMI) and spin–orbit torque effects in CuIr/CoFeB/MgO heterostructures. To this end, harmonic Hall measurements and current induced domain wall motion experiments are performed. The motion of domain walls at zero applied field due to current demonstrates the presence of DMI in this system. We determine the strength of the DMI to be D=+5 ± 3 μJ/m2 and deduce right-handed chirality in domain walls showing a partial Néel type spin structure. To ascertain the torques, we perform a second harmonic measurement to quantify the damping- and field-like current induced effective fields as a function of the magnetization direction. From the angular dependent analysis, we identify non-negligible higher order terms for polar magnetization angles θ>0, which need to be included when considering the effective manipulation of spins by current.

Manipulating the magnetic and transport properties by CuIr thickness in CoFeB/CuIr/IrMn multilayers

“…However, studies containing CuIr alloys in the literature are very limited and they mostly focus on spin Hall effect (SHE) and spin-orbit torque (SOT) applications by using the FM/CuIr/FM trilayered or CuIr/FM bilayered structures [27][28][29][30][31][32][33][34]. SOT studies with CuIr indicate that the dampinglike term stands out more than the field-like term [32].…”

Level attraction and exceptional points in a resonant spin-orbit torque system

“…Spin-orbit torques play an important role in spintronics [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], with numerous applications including electric control and magnetization switching [20][21][22], coherent excitation and amplification of spin waves [23][24][25][26], currentinduced collective dynamics of topological spin textures [27][28][29][30][31], memory and logic devices [32][33][34], and neuromorphic computing [35]. Spin-orbit torque oscillators are of particular interest for many applications [36][37][38][39][40], including damping and antidamping torques [41] and other nontrivial features in high frequency response [42,43].…”

Exchange spring-like inhomogeneous states in a ferromagnetic wire with current

“…For several decades now, the interaction of an electric current with a ferromagnetic domain structure has been one of the central issues of spintronics [1][2][3][4][5][6][7][8][9][10]. A significant number of mechanisms have been proposed for the effect of current carriers on inhomogeneous magnetization, including adiabatic and nonadiabatic transfer of spin momentum, as well as spin-orbit interaction through the Rashba effect, the Dzyaloshinskii-Moriya interaction, etc.…”

“…We see that the second stage in the evolution of the exchange spring with increasing current consists in its gradual compression and localization in the middle part of the film. The change in the calculated magnetization profiles with increasing current along with the dependences (5), ( 6), (8) are shown in Fig. 1.…”