Evidence of Electrical Switching of the Antiferromagnetic Néel Vector

Recently, field-free switching of antiferromagnetic (AFM) Néel vector via spin-orbit torque (SOT) attracting worldwide attention. By applying a writing current in the AFM or the normal metal (NM)/AFM bilayer, in a patterned multi-terminal structures, the measured resistance shows recurring signals due to supposedly electrical switching of the AFM Néel vector. However, in this work, we demonstrate that similar signals can be observed in such patterned structures, with and without the AFM layer [1]. The strength of the signal is also greatly affected by different metals and substrates. We show that under a large writing current density beyond the Ohmic regime, the multi-terminal devices can generate unintended anisotropic thermal gradient and voltages. Therefore, this switching signal may not be the conclusive evidence of the SOT switching of AFM, but the thermal artifacts of patterned metal structures on substrate.

[1] C. C. Chiang, S. Y. Huang, D. Qu, P. H. Wu, and C. L. Chien, Phys. Rev. Lett., in press (2019).