Enhanced coercivity of exchange-bias Fe/MnPd bilayers

We present detailed studies of the enhanced coercivity of exchange-bias bil ayer Fe/MnPd, both experimentally and theoretically. We have demonstrated t hat the existence of large higher-order anisotropies due to exchange coupli ng between different Fe and MnPd layers can account for the large increase of coercivity in the Fe/MnPd system. The linear dependence of coercivity on inverse Fe thickness is well explained by a phenomenological model by intr oducing higher-order anisotropy terms into the total free energy of the sys tem. (C) 1999 American Institute of Physics. [S0003-6951(99)04031-0].