Investigation of exchange bias in FeMnC/FeMn bilayers

The exchange bias (EB) effect and magnetic domain structures of FeMnC/FeMn bilayers prepared by a facing target sputtering system were studied. Unusual doubly shifted hysteresis loops were observed in a series of FeMnC/FeMn bilayers when different magnetic fields were applied to induce the exchange bias. The temperature dependences of the double shifted loops were measured and the ferromagnetic resonance measurement reveals the existence of EB. The correlation between the microscopic domain structures and the magnetization reversal processes was discussed, which suggests that the domain structure distribution of the antiferromagnetic layer is responsible for the loop shift.