Influences on relaxation of exchange biasing in NiO/Ni66Co18Fe16 bilayers

The stability of the exchange biasing field, H-eb has been studied for NiO/ Ni66Co18Fe16 bilayers. A forced antiparallel alignment of the ferromagnetic magnetization to H-eb results in a gradual decrease and even a reversal of H-eb. The decrease of H-eb increases with temperature and is independent o f the external field and NiO layer thickness. This decrease can be interpre ted by a thermally assisted relaxation process. A new effect of the relaxat ion process on H-eb is demonstrated by using different cooling rates. (C) 1 998 American Institute of Physics.