Thermal evolution of magnetization reversal processes in trained and non-trained nanocrystalline exchange biased Ni80Fe20/Co-O bilayers

We have studied the magnetization reversal processes in exchange biased Ni80Fe20/Co-O bilayers through the anisotropic magnetoresistance curves measured in the range of temperatures comprehended between 50 and 300 K. As a consequence of the strong training effect, the magnetoresistance measurements reveal large differences between first and subsequent reversals, mainly at low temperatures. As long as the main mechanism governing the first reversal seems to be basically the inverse domain wall propagation, rotational process are taking place in subsequent reversals