Dynamics of Spontaneous Magnetization Reversal in Exchange Biased Heterostructures

TL;DR

This study investigates how cooling protocols influence spontaneous magnetization reversal in exchange-biased heterostructures, revealing that slower cooling and thermal cycling near the Néel temperature enhance the reversal, indicating an energetically favored process.

Contribution

It provides new insights into the dynamics of magnetization reversal, highlighting the effects of cooling rate and thermal cycling near the Néel temperature on spontaneous reversal behavior.

Findings

Slower cooling enhances magnetization reversal.

Thermal cycling near $T_N$ increases reversal magnitude.

Reversal is energetically favored, contrary to positive exchange bias understanding.

Abstract

The dependence of thermally induced spontaneous magnetization reversal on time-dependent cooling protocols was studied. Slower cooling and longer waiting close to the N\`{e}el temperature of the antiferromagnet ($T_N$) enhances the magnetization reversal. Cycling the temperature around $T_N$ leads to a thermal training effect under which the reversal magnitude increases with each cycle. These results suggest that spontaneous magnetization reversal is energetically favored, contrary to our present understanding of positive exchange bias.