Controlled Localized Domain Wall Writing in Antiferromagnetic Nano Stripes With In-Plane Transverse Currents

In order for textures in intrinsic antiferromagnets to be applied in proposed spintronics devices, localized and controllable writing is required. Here, the feasibility of a simple scheme for spin-Hall torque driven localized writing of chiral antiferromagnetic (AFM) domain wall (DW) pairs at a chosen location in AFM nano stripes is investigated. Short voltage pulses causing in-plane current-injection across transverse contacts in the heavy metal trigger a localized horizontal boundary-nucleated reverse AFM domain that propagates throughout the width to the opposite boundary, defining a locally written DW pair without affecting information in other parts of the device. The nucleation mechanism is examined, indicating exchange torque governing. A diagram of the number of DW-pairs written as a function of applied writing pulse amplitude and pulse duration is shown for a generic antiferromagnet, illustrating the degree of control required of the excitation protocol. Simulations of write and drive pulses are also presented, showing that the slight current bending around the writing contacts does not impose any significant pinning nor nucleation of unwanted textures for a typical driving amplitude. The advantages of this simple scheme are that it does not require any component for vertical spin-polarized current injection nor lasers for writing as in previous proposals.