Antiferromagnets are enriching spintronics research by many favorable properties that include insensitivity to magnetic fields, neuromorphic memory characteristics, and ultra-fast spin dynamics. Designing memory devices with electrical writing and reading is one of the central topics of antiferromagnetic spintronics. So far, such a combined functionality has been demonstrated via 90° reorientations of the Néel vector generated by the current-induced spin orbit torque and sensed by the linear-response anisotropic magnetoresistance. Here we show that in the same antiferromagnetic CuMnAs films as used in these earlier experiments we can also control 180° Néel vector reversals by switching the polarity of the writing current. Moreover, the two stable states with opposite Néel vector orientations in this collinear antiferromagnet can be electrically distinguished by measuring a second-order magnetoresistance effect. We discuss the general magnetic point group symmetries allowing for this electrical readout effect and its specific microscopic origin in CuMnAs.

Donostia International Physics Center Paseo Manuel de Lardizabal 4 Donostia San Sebastian 20018 Spain

Faculty of Mathematics and Physics Charles University Prague Ke Karlovu 3 12116 Prague 2 Czech Republic

Hitachi Cambridge Laboratory Hitachi Europe LTD JJ Thomson Avenue Cambridge CB3 0HE United Kingdom

Institut für Festkörper und Materialphysik Technische Universität Dresden 01062 Dresden Germany

Institute of Physics Czech Academy of Sciences Cukrovarnická 10 160 00 Prague 6 Czech Republic

Max Planck Institute for Chemical Physics of Solids 01187 Dresden Germany

School of Physics and Astronomy University Of Nottingham NG7 2RD Nottingham United Kingdom

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Ultrashort spin-orbit torque generated by femtosecond laser pulses