Based on Monte Carlo method, the characteristic of exchange bias is discussed in diluted antiferromagnets in FM/AFM bilayers by changing the dilute concentration. The simulation results show that the exchange bias in FM/AFM bilayers can be enhanced significantly by introducing nonmagnetic atoms into the AFM layers. And there is a maximum in the diagram of exchange bias as a function of the dilute concentration, i.e., the exchange bias at first increases then decreases with increasing concentration of dilution at the same temperature. Besides, the maximum of the exchange bias occurs at lower concentration for higher temperature. These are consistent with the results of Phys. Rev. Lett. 96 117204 (2006). The cause of these results is that the spin distribution and the magnetic domain structure change greatly when varying dilute concentration. The exchange bias is maximal when the positive and the negative magnetic domains form a connected network. In addition, at the same concentration of dilution, by comparing the results of the random and regular dilution, we find that the exchange bias are more strongly increased by regular dilution than by random dilution for the FM/AFM bilayers, which shows further that the characteristic of exchange bias in FM/AFM bilayers depends on the interface spin-microstructure.

Using a method based on the system energy described by Smith and Beljers, the ferromagnetic resonance in ferromagnetic (FM)/Antiferromagnetic (AFM) bilayers under the stress field is studied. The thin FM film is taken to be a single crystal with cubic and uniaxial magnetocrystalline anisotropies, while the thickness of AFM layer is thin enough for its energy to be neglected. Numerical calculations show that the stress field will affect resonance curve only under weak magnetic field, and the critical field strength which distinguishes the weak from the strong external field depends on the direction of the stress field only.