Chiral Symmetry Breaking for Deterministic Switching of Perpendicular Magnetization by Spin-Orbit Torque.
Symmetry breaking is a characteristic to determine which branch of a bifurcation system follows upon crossing a critical point. Specifically, in spin-orbit torque (SOT) devices, a fundamental question arises: how can the symmetry of the perpendicular magnetic moment be broken by the in-plane spin polarization? Here, we show that the chiral symmetry breaking by the antisymmetric Dzyaloshinskii-Moriya interaction (DMI) can induce the deterministic SOT switching of the perpendicular magnetization. By introducing a gradient of saturation magnetization or magnetic anisotropy, the dynamic noncollinear spin textures are formed under the current-driven SOT, and thus, the chiral symmetry of these dynamic spin textures is broken by the DMI, resulting in the deterministic magnetization switching. We introduce a strategy to induce an out-of-plane (z) gradient of magnetic properties as a practical solution for the wafer-scale manufacture of SOT devices.
['Wu|Hao|H|http://orcid.org/0000-0001-8608-3035', 'Nance|John|J|', 'Razavi|Seyed Armin|SA|', 'Lujan|David|D|', 'Dai|Bingqian|B|', 'Liu|Yuxiang|Y|', 'He|Haoran|H|', 'Cui|Baoshan|B|', 'Wu|Di|D|', 'Wong|Kin|K|', 'Sobotkiewich|Kemal|K|', 'Li|Xiaoqin|X|', 'Carman|Gregory P|GP|', 'Wang|Kang L|KL|http://orcid.org/0000-0003-0487-5464']
chiral symmetry breaking Dzyaloshinskii−Moriya interaction magnetic gradient spin−orbit torque