Electrical modulation of antiferromagnetic easy axis ($N\acute{e}el$ vector) in exchange-biased structures

Abstract

Antiferromagnetic materials are a promising candidate for future memory device due to their robustness against external magnetic field, fast switching speed and large storage density. However, reading and writing the antiferromagnetic order is difficult due to zero net magnetization. Therefore, electrical reading and writing is of significant importance in realizing an antiferromagnetic memory device. In this thesis, I studied electrical manipulation of Néel vector in exchange-biased structures by utilizing antiferromagnets as a spin source and ferromagnets as a detection layer. Nonvolatile and reversible switching behavior of $N\acute{e}el$ vector is achieved in-plane, and the modulation range is $45^\circ$ quantified by the planar Hall effect. The mechanism of the electrical switching of the Néel vector is attributed to the spin orbit torque originating from the antiferromagnetic layer itself and the concurrent switching of the ferromagnet and antiferromagnet. In addition, since the switching behavior exhibits memristive characteristics, exchange-biased structures can not only contribute to the realization of the antiferromagnetic memory, but also to the neuromorphic application.