Modulation of domain wall dynamics in TbFeCo single layer nanowire

TL;DR

This paper demonstrates the controlled creation and manipulation of magnetic domain walls in a TbFeCo nanowire using pulse currents and external fields, highlighting potential for spin-torque memory devices.

Contribution

It introduces a method to write and modulate domain walls in a single-layer nanowire with precise control over domain size and position.

Findings

Critical current density for domain wall motion: 3.5×10^10 A/m^2

Domain size can be tuned by external magnetic field or pulse length

Successful demonstration of domain wall control in TbFeCo nanowire

Abstract

We demonstrate the possibility to write and modulate the magnetic domain walls in a TbFeCo single layer nanowire (300 nm width, 150 $\mu$m length). To realize this, a tiny magnetic domain was nucleated by an Oersted field produced by a 1.6 MHz pulse current (35 mA in amplitude, 5-40 ns in length) crossed the wire. To write the wall to the wire, a DC current was used to drive the nucleated domain (with two walls in two sides) to the wire in accordance with spin-transfer torque mechanism. A critical current density of $J_c = 3.5\times10^{10} Am^{-2}$ was required to control the motion of the walls in the wire. It was found that the size of the domain moving in the wire could be adjusted by either external field or the length of the nucleated pulse current. This could be considered as an important note for writing process in domain wall spin-torque devices, especially, memory elements.