Magnetization reversal in ferromagnetic spirals via domain wall motion

We present a combination of analytic and simulated results describing the reliable field driven motion of adomain wall through the arms of aferromagnetic spiralnanowire. The spiral geometry is capable of taking advantage of the benefits of both straight and circularwires.Measurements of the in-plane components of the spirals' magnetization can be used to determine the angular location of thedomain wall, impacting the magnetoresistive applications dependent on thedomain wall location. The spirals' magnetization components are found to depend on the spiral parameters: the initial radius and spacing between spiral arms, along with thedomain wall location. The magnetization is independent of the parameters of the rotating field used to move thedomain wall, and therefore the model is valid for current induceddomain wall motion as well. The speed of thedomain wall is found to depend on the frequency of the rotating driving field, and thedomain wall speeds can be reliably varied over several orders of magnitude. We further demonstrate a technique capable of injecting multipledomain walls and show the reliable and unidirectional motion ofdomain walls through the arms of the spiral.

Source: Applied Physics Letters - November 16, 2016 Category: Physics Authors: Ryan D. Schumm and Andrew Kunz Source Type: research