Memristive behavior of field-driven domain-wall motion in a width-modulated structure with multiple Hall crosses

Abstract

The remarkable property of a memristor is that it provides multiple resistance states by remembering the current or voltage history associated with the magnetic flux and charge in the device. We investigate the domain wall (DW) motion in a multiple Hall crosses (MHCs) structure to realize the memristive DW device. We fabricated perpendicular magnetic anisotropy (PMA) micro-wires for a [Co/Pt]4 multilayer stack, and they contain MHCs with various widths. When an external field is applied, a DW alternately passes through each Hall cross, thereby creating a hysteresis loop with various magnitudes of Hall resistance states depending on the DW position. Because the measured Hall signal relies on the DW position, which is a function of the history of the field, the basic requirements of a memristor are satisfied. In addition to the anomalous Hall signal, the movement of the DW in the PMA system by field pulses has been recorded using a Kerr microscope to confirm the DW position. The results reveal that the DW motion in the width-modulated MHCs system can be used as a promising test bed and/or application of the memristive DW-motion device.