Angular dependence of exchange anisotropy in Ni81Fe19/CrMnPtx bilayers

We have investigated the unidirectional exchange anisotropy between a ferro magnetic (FM) Ni81Fe19 film and a disordered antiferromagnetic (AF) CrMnPtx (x=3, 6, or 9) film. The angular dependence of the exchange coupling in th ese FM/AF bilayers has been measured. We show that the complex angular depe ndence of this exchange coupling can be understood by a simple Stoner-Wohlf arth model involving only a uniaxial anisotropy and a unidirectional exchan ge coupling. Numerical results are in excellent agreement with the experime ntal data. (C) 1999 American Institute of Physics. [S0021-8979(99)04720-9].