In P-y/CrAl bilayers (where P-y = Ni81Fe19), the coercivity at room tempera
ture is found to be a linear function of 1/t(FM)(3/2), indicating the exist
ence of random exchange interaction at the FM/AFM interface (FM = ferromagn
etic, AFM = antiferromagnetic). The AFM layer thickness dependencies of the
H-e and H-c are also studied.