Intrinsic exchange bias and its origin in spin-glass-like disordered La0.8Sr1.2CoO4 cobaltite

Exchange bias phenomena have been investigated in the single-layered perovskite cobaltite La0.8Sr1.2CoO4 exhibiting spin-glass-like behavior at low temperature. The field cooled magnetic hysteresis loops display both horizontal and vertical shifts. The training effect of exchange bias behavior is also observed, which can be explained in terms of a spin configuration relaxation model. In addition, exchange bias is found to depend strongly on measuring field as well as the cooling field. This behavior is suggested to originate from the interfacial exchange coupling between the disordered spin-glass-like phases and ferromagnetic clusters, where the spin configurations are affected by the field strength. This magnetically tunable exchange bias has the potential in view of the use of cobaltites in spintronics.