Quenching of an antiferromagnet into high resistivity states using electrical or ultrashort optical pulses

Abstract

Electrical and short optical pulses can be used to deterministically induce and reverse a nano-fragmented domain state in antiferromagnetic CuMnAs, in a process that can be probed via changes in the resistance of the system. Antiferromagnets are of potential use in the development of spintronic devices due to their ultrafast dynamics, insensitivity to external magnetic fields and absence of magnetic stray fields. Similar to their ferromagnetic counterparts, antiferromagnets can store information in the orientations of the collective magnetic order vector. However, the readout magnetoresistivity signals in simple antiferromagnetic films are weak, and reorientation of the magnetic order vector via optical excitation has not yet been achieved. Here we report the reversible and reproducible quenching of antiferromagnetic CuMnAs into nano-fragmented domain states using either electrical or ultrashort optical pulses. The changes in the resistivity of the system approach 20% at room temperature, which is comparable to the giant magnetoresistance ratios in ferromagnetic multilayers. We also obtain a signal readout by optical reflectivity.