Ferromagnetic resonance in ferromagnetic/antiferromagnetic bilayers under the stress field

Based on the energy of equilibrium, the ferromagnetic resonance for ferromagnetic (FM)/antiferromagnetic (AFM) bilayers under the stress field is studied by using Smith and Beljers's method. The thin FM film is taken to be a single crystal with cubic and uniaxial magnetocrystalline anisotropies, while the thickness of AFM layer is semi-infinite but with single uniaxial magnetocrystalline anisotropies. Numerical calculations show that there are two branches for FM resonance modes divided by the critical field, which distinguishes the weak and strong external field. The critical field depends on the direction of stress field and the interfacial “turning” coefficient. Interestingly, the stress field and the interfacial “turning” coefficient both affect FM resonance only under the weak magnetic field. On the other hand, the variety of the stress field angle can alter the direction of magnetocrystalline anisotropies axis of FM layer.