Static and dynamic behavior of 360∘domain walls in patterned thin films

Abstract

We study the static and dynamic behavior of transverse domain walls and 360${}^{\ensuremath{\circ}}$ domain walls in a thin film of isotropic material including pinning effects caused by geometric defects in the form of triangular antinotches. In terms of the static interaction, our model reduces the domain walls to sources of magnetic charge, allowing an electrostatic-like description of their interaction. Such a concept was applied to both of these magnetic textures allowing us to estimate the shortest distance between the antinotches at which the domains walls can be located, while still being pinned. Regarding the domain walls' dynamical behavior, accurate micromagnetic simulations of our system were performed, characterizing their recombination times as well as showing that triangular notches allow the coherent movement of single and arrays of 360${}^{\ensuremath{\circ}}$ domain walls by pulses of spin current. This behavior could not be observed in single transverse walls given the long-range interaction that they present, impeding coherent domain wall motion. These findings allow us to estimate the maximum 360${}^{\ensuremath{\circ}}$ domain wall density, observing an increase by a factor of four when compared to systems based on single transverse domain walls, which potentially gives our system important industrial applications.