Hard-soft bilayers are analogous to prototype exchange-biased ferromagnetic -antiferromagnetic systems as the minor loop of the soft layer is biased by the hard and furthermore they offer bias layer tunability. In sputtered CoPt/Co hard-soft bilayers we demonstrate that the exchange bias field shows a linear dependence on the hard layer magnetization, while the coercivity shows a quadratic dependence. Analysis of the minor hysteresis loop features supported by Monte-Carlo simulations provide clear evidence that the coercivity of the soft layer is mainly determined by the tunable randomness of the domain state of the hard layer.
@article{arxiv.1603.09618,
title = {Coercivity and random interfacial exchange coupling in CoPt/Co films},
author = {V. Alexandrakis and D. Kechrakos and N. Moutis and D. Niarchos and G. Hadjipanayis and I. Panagiotopoulos},
journal= {arXiv preprint arXiv:1603.09618},
year = {2016}
}