Dynamics of Successive Minor Hysteresis Loops

TL;DR

This study investigates how successive minor hysteresis loops evolve in disordered ferromagnetic multilayers, revealing the dynamics of magnetization reversal and the conditions for loop stabilization.

Contribution

It provides new insights into the time-dependent magnetization reversal processes and the conditions leading to stable, reproducible hysteresis loops in disordered ferromagnets.

Findings

Nucleation, domain expansion, and annihilation govern loop growth.

Loop growth ceases when domain populations balance.

Reproducibility occurs when reversal times stabilize.

Abstract

Cumulative growth of successive minor hysteresis loops in Co/Pd multilayers with perpendicular anisotropy was studied in the context of time dependent magnetization reversal dynamics. We show that in disordered ferromagnets, where magnetization reversal involves nucleation, domains' expansion and annihilation, differences between the time dependencies of these processes are responsible for accumulation of nuclei for rapid domain expansion, for the asymmetry of forward and backward magnetization reversals and for the respective cumulative growth of hysteresis loops. Loops stop changing and become macroscopically reproducible when populations of upward and downward nucleation domains balance each other and the respective upward and downward reversal times stabilize.