Performance of switch between exchange bias and coercivity: Influences of antiferromagnetic anisotropy and exchange coupling

The study on temperature dependence of exchange bias field and coercivity is crucial to solving the writing/reading dilemma in magnetic recording. Motivated by recent experimental findings, a complete switch between exchange bias field and coercivity with temperature is proposed, and the performance, characterized by average switching temperature ( T S ) and switching temperature width ( AT W ), controlled by antiferromagnetic anisotropy ( K AF ) and exchange coupling ( J AF ) constants is studied based on a MonteCarlo simulation. The results show that a linear relationship between T S and K AF is established when K AF is above a critical value, while T S is weakly influenced by J AF . On the contrary, AT W is insensitive to K AF , while strongly depends on J AF . Besides overcoming thermal energy, the increase of K AF for a small J AF guarantees the completely frozen states in the antiferromagnetic layers during magnetizing at higher temperature, below which the exchange bias field exists with a negligible coercivity. Otherwise, for a large J AF , the uncompensated antiferromagnetic magnetization behavior during the ferromagnetic magnetization reversal becomes complicated, and the switching process in the low temperature range depends on the irreversibility of uncompensated antiferromagnetic magnetization reversal during magnetizing, while in the high temperature range mainly influenced by the field-cooling process, resulting in a large AT W . This work provides an opportunity to control/optimize the performance of the temperatureinduced switch between unidirectional and uniaxial symmetries through precisely tuning K AF and/or J AF to meet different application demands in the next generation information technology. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

The study on the temperature dependence of exchange bias field and coercivity is crucial for solving the writing/reading dilemma in magnetic recording. Based on recent experimental findings, a complete switch between the exchange bias field and coercivity with temperature is proposed. The performance, characterized by average switching temperature (TS) and switching temperature width (ATW), is controlled by antiferromagnetic anisotropy (KAF) and exchange coupling (JAF) constants.