Spin-orbit torques, which utilize spin currents arising from the spin-orbit coupling, offer a novel method to electrically switch the magnetization with perpendicular anisotropy. However, the necessity of an external magnetic field to achieve a deterministic switching is an obstacle for realizing practical spin-orbit torque devices with all-electric operation. Here, we report a field-free spin-orbit torque switching by exploiting the domain wall motion in an anti-notched microwire with perpendicular anisotropy, which exhibits multi-domain states stabilized by the domain wall surface tension. The combination of spin-orbit torque, Dzyaloshinskii-Moriya interaction, and domain wall surface tension induced geometrical pinning allows a deterministic control of the domain wall and offers a novel method to achieve a field-free spin-orbit torque switching. Our work demonstrates the proof of concept of a perpendicular memory cell which can be readily adopted in a three-terminal magnetic memory.
@article{arxiv.1807.06287,
title = {Field-free spin-orbit torque switching from geometrical domain wall pinning},
author = {Jong Min Lee and Kaiming Cai and Guang Yang and Yang Liu and Rajagopalan Ramaswamy and Pan He and Hyunsoo Yang},
journal= {arXiv preprint arXiv:1807.06287},
year = {2018}
}