Domain wall dynamics in a single CrO$_2$ grain

TL;DR

This study investigates the magnetization reversal mechanisms in a single CrO₂ grain, revealing distinct Barkhausen jump behaviors along different magnetic directions and highlighting the sample's high purity through micromagnetic analysis.

Contribution

It provides a detailed analysis of Barkhausen jumps in a single CrO₂ grain for both easy and hard magnetization directions, supported by micromagnetic simulations.

Findings

Magnetization reversal occurs through few configuration paths.

Different Barkhausen jump statistics for easy and hard directions.

High sample purity indicated by limited reversal pathways.

Abstract

Recently we have reported on the magnetization dynamics of a single CrO$_2$ grain studied by micro Hall magnetometry (P. Das \textit{et al.}, Appl. Phys. Lett. \textbf{97} 042507, 2010). For the external magnetic field applied along the grain's easy magnetization direction, the magnetization reversal takes place through a series of Barkhausen jumps. Supported by micromagnetic simulations, the ground state of the grain was found to correspond to a flux closure configuration with a single cross-tie domain wall. Here, we report an analysis of the Barkhausen jumps, which were observed in the hysteresis loops for the external field applied along both the easy and hard magnetization directions. We find that the magnetization reversal takes place through only a few configuration paths in the free-energy landscape, pointing to a high purity of the sample. The distinctly different statistics of the Barkhausen jumps for the two field directions is discussed.