Effects of an oscillating field on magnetic domain patterns: Numerical and theoretical studies on the concentric-ring patterns surrounding a strong defect

TL;DR

This study combines numerical simulations and theoretical analysis to investigate how high-frequency oscillating magnetic fields influence the formation of concentric-ring domain patterns around defects, revealing threshold behaviors and pattern characteristics.

Contribution

It provides a combined numerical and theoretical framework to understand the formation and thresholds of concentric-ring magnetic domain patterns under oscillating fields.

Findings

Concentric-ring patterns occur near the threshold of uniform patterns in high-frequency fields.

Theoretical thresholds match well with numerical results in high-frequency regimes.

The analysis estimates characteristics of domain patterns effectively at high frequencies.

Abstract

Oscillating fields can make domain patterns change into various types of structures. Numerical simulations show that concentric-ring domain patterns centered at a strong defect are observed under a rapidly oscillating field in some cases. The concentric-ring pattern appears near the threshold of spatially-uniform patterns in high-frequency cases. The threshold is theoretically estimated and the theoretical threshold is in good agreement with numerical one in a high-frequency region. The theoretical analysis gives also good estimations of several characteristics of domain patterns for high-frequencies.