State transitions and hysteresis in a transverse magnetic island chain

TL;DR

This paper investigates the magnetization behavior and state transitions in a chain of dipole-coupled magnetic islands under an external magnetic field, revealing complex hysteresis and stability phenomena influenced by anisotropy and geometry.

Contribution

It introduces a theoretical model analyzing state stability and transitions in magnetic island chains, highlighting the impact of anisotropy and geometry on magnetization behavior.

Findings

Identification of three distinct uniform magnetization states.

Prediction of hysteresis and transition points dependent on anisotropy.

Dependence of magnetization curves on dipolar and anisotropy constants.

Abstract

A chain of dipole-coupled elongated magnetic islands whose long axes are oriented perpendicular to the chain is studied for its magnetization properties. With a magnetic field applied perpendicular to the chain, the competition between dipolar energy, shape anisotropy, and field energy leads to three types of uniform states with distinct magnetizations: (1) oblique to the chain, (2) perpendicular to the chain, and (3) zero due to having alternating dipoles. The response of these states to a slowly varying field is analyzed, focusing on their stability limits and related oscillation modes, and the dependencies on the dipolar and anisotropy constants. Based on identifiable transitions among the three states and their instability points, the theoretically predicted zero-temperature magnetization curves show significant dependence on the anisotropy. The model suggests a path for designing advanced materials with desired magnetic properties. Different geometries and magnetic media for the islands are considered.