In this work, we studied the relaxation of the remanent magnetization of antiferromagnetically ordered ferrihydrite nanoparticles under the conditions of realization of the exchange bias effect for these systems. Magnetization relaxation is characterized by a logarithmic dependence on time, which is typical for thermo-activation processes of the hopping of the magnetic moment of particles through potential barriers caused by magnetic anisotropy. The energy of the barriers obtained from processing the data on relaxation of the remanent magnetization (under the conditions of field cooling) significantly exceeds that for ordinary conditions (zero field cooling). The observed difference indicates the possibility of using the residual magnetization relaxation process to analyze the mechanisms responsible for the effect of exchange bias in antiferromagnetic nanoparticles and obtain the parameters characterizing the exchange coupling of magnetic subsystems in such objects.
Giant zero field cooled spontaneous exchange bias effect in phase separated La1.5Sr0.5CoMnO6
