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 (TN) enhances the magnetization reversal. Cycling the temperature around TN 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.
@article{arxiv.cond-mat/0612113,
title = {Dynamics of Spontaneous Magnetization Reversal in Exchange Biased Heterostructures},
author = {Zhi-Pan Li and Casey W. Miller and Igor V. Roshchin and Ivan K. Schuller},
journal= {arXiv preprint arXiv:cond-mat/0612113},
year = {2009}
}