Critical angle behaviour of exchange bias and coercivity with field angle in exchange coupled CoFe/MnIr bilayers

In this work, we measured the H_ex and H_c with field angle in the conditions of d_AF>d_c and d_AF< d_c. The critical angle behavior in polycrystalline CoFe/Mnlr bilayers has been systematically analyzed by using the modified S-W model. Magnetization curves with magnetic field angle from 0 to 180 degree were measured with a Magneto-Optic Kerr Effect (MOKE) instrument. The CoFe layer thickness is constant of 100 nm, therefore, the critical angle depend on J values.