ANGULAR-DEPENDENCE OF EXCHANGE COUPLING IN FERROMAGNET ANTIFERROMAGNET BILAYERS/

Angular dependence of the exchange coupling in a NiFe/CoO bilayer film has been measured, Different angular dependence and symmetry have bee n observed for the exchange field H-E and the coercivity H-C. The valu es of H-E and H-C are due to unidirectional and uniaxial components of the magnetic anisotropy energy, in which the odd and the even terms l ead to H-E and H-C, respectively. The proposed free energy accounts fo r the experimental results.