Exchange bias in the layered cobaltite Sr1.5Pr0.5CoO4

We investigate the exchange bias phenomenon in the layered cobaltite Sr1.5Pr0.5CoO4 by using magnetometry. The exchange bias is strongly dependent on the cooling magnetic field as well as the measuring field. These results suggest that the exchange coupling at the interfaces between the ferromagnetic (FM) regions and the spin-glass (SG) regions may induce an exchange anisotropy. The observed exchange bias effect is suggested to originate from the pinning to FM moments by frozen spins in the SG regions along the cooling field direction. Our results also expand the concept of the magnetically tunable exchange bias, which can contribute to the potential applications for spintronic devices.