We consider mechanism of exchange coupling based on interaction between electrons in nonmagnetic layer. Depending on ratio of inverse time of diffusion of electrons between ferromagnetic layers and ferromagnetic splitting of conducting electrons this mechanism describes transition from ferromagnetic to noncollinear ordering of magnetizations of ferromagnetic layers.
@article{arxiv.cond-mat/0209084,
title = {Theory of exchange coupling in disordered magnetic multilayers},
author = {Zyuzin A. Yu},
journal= {arXiv preprint arXiv:cond-mat/0209084},
year = {2009}
}