Current Controlled Magnetization Switching in Cylindrical Nanowires for High-Density 3D Memory Applications

TL;DR

This paper demonstrates controlled domain wall motion in cylindrical nanowires with alternating cobalt and nickel segments, enabling high-density 3D memory applications through current-assisted pinning and depinning.

Contribution

It introduces a method to control domain wall position in segmented nanowires using current pulses, advancing 3D memory device technology.

Findings

Domain walls can be reliably moved using current pulses.

Magnetoresistance and magnetic force microscopy confirm domain wall control.

Bit density can be increased by segmenting nanowires for multi-bit storage.

Abstract

A next-generation memory device utilizing a three-dimensional nanowire system requires the reliable control of domain wall motion. In this letter, domain walls are studied in cylindrical nanowires consisting of alternating segments of cobalt and nickel. The material interfaces acting as domain wall pinning sites, are utilized in combination with current pulses, to control the position of the domain wall, which is monitored using magnetoresistance measurements. Magnetic force microscopy results further confirm the occurrence of current assisted domain wall depinning. Data bits are therefore shifted along the nanowire by sequentially pinning and depinning a domain wall between successive interfaces, a requirement necessary for race-track type memory devices. We demonstrate that the direction, amplitude and duration of the applied current pulses determine the propagation of the domain wall across pinning sites. These results demonstrate a multi-bit cylindrical nanowire device, utilizing current assisted data manipulation. The prospect of sequential pinning and depinning in these nanowires allows the bit density to increase by several Tbs, depending on the number of segments within these nanowires.