The spin-Hall effect describes the interconversion of charge currents and spin currents, enabling highly efficient manipulation of magnetization for spintronics. Symmetry conditions generally restrict polarizations of these spin currents to be orthogonal to both the charge and spin flows. Spin polarizations can deviate from such direction in nonmagnetic materials only when the crystalline symmetry is reduced11. Here we experimentally show control of the spin polarization direction by using a non-collinear antiferromagnet Mn3GaN, in which the triangular spin structure creates a low magnetic symmetry state while maintaining a high crystalline symmetry. We demonstrate that epitaxial Mn3GaN/Permalloy heterostructures can generate unique types of spinHall torques at room temperature corresponding to unconventional spin polarizations collinear to spin currents or charge currents which are forbidden in any sample with two-fold rotational symmetry. Our results demonstrate an approach based on spin-structure design for controlling spinorbit torque, paving the way for further progress in the emergent field of antiferromagnetic spintronics.
@article{arxiv.1912.12586,
title = {Controlling spin current polarization through non-collinear antiferromagnetism},
author = {T. Nan and C. X. Quintela and J. Irwin and G. Gurung and D. F. Shao and J. Gibbons and N. Campbell and K. Song and S. Y. Choi and L. Guo and R. D. Johnson and P. Manuel and R. V. Chopdekar and I. Hallsteinsen and T. Tybell and P. J. Ryan and J. W. Kim and Y. S. Choi and P. G. Radaelli and D. C. Ralph and E. Y. Tsymba and M. S. Rzchowski and C. B. Eom},
journal= {arXiv preprint arXiv:1912.12586},
year = {2020}
}