Efficient Spin Torques in Antiferromagnetic <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>CoO</mml:mi><mml:mo>/</mml:mo><mml:mi>Pt</mml:mi></mml:math> Quantified by Comparing Field- and Current-Induced Switching
Lorenzo Baldrati, Christin Schmitt, Olena Gomonay, Romain Lebrun, R. Ramos, Eiji Saitoh, Jairo Sinova, Mathias Kläui
Abstract
We achieve current-induced switching in collinear insulating antiferromagnetic $\mathrm{CoO}/\mathrm{Pt}$, with fourfold in-plane magnetic anisotropy. This is measured electrically by spin Hall magnetoresistance and confirmed by the magnetic field-induced spin-flop transition of the CoO layer. By applying current pulses and magnetic fields, we quantify the efficiency of the acting current-induced torques and estimate a current-field equivalence ratio of $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}\text{ }\text{ }\mathrm{T}\text{ }{\mathrm{A}}^{\ensuremath{-}1}\text{ }{\mathrm{m}}^{2}$. The N\'eel vector final state $(\mathbit{n}\ensuremath{\perp}\mathbit{j})$ is in line with a thermomagnetoelastic switching mechanism for a negative magnetoelastic constant of the CoO.