Cooling-field dependence of exchange bias in Mg-diluted Ni1−xMgxO/Ni granular systems

The exchange-bias (EB) properties of Mg-diluted Ni1−xMgxO/Ni (0⩽x⩽0.3) granular systems have been investigated. Magnetic dilution with Mg greatly affects the EB field and the coercivity. The temperature dependence of the EB field and the coercivity can be explained in terms of formation of domain states. The value of the EB field increases and shows a maximum value with increasing cooling field, which can be explained by the competition between the field-dependent Zeeman energy and the exchange interaction at the interface.