New insight in hard magnetism of cobalt-doped α-Fe2O3

Abstract

In this work, hard magnetism was studied on cobalt-doped α-Fe2O3 particles, with special regard to the evolution of coercive fields as well as exchange bias fields. It was found that the coercivity of calcined sample fell into decline as temperature rose. Quite on the contrary, the sample prior to calcination exhibited a monotonical increment as increasing temperature. Further studies showed that lattice defects and voids in α-Fe2O3 host, Co-doped α-Fe2O3 colonies, FeOOH magnetic lattice, and CoFe2O4 impurity phase were responsible for such significantly distinct magnetism evolution. The exhibited large coercivity beyond 10 kOe and pronounced exchange bias field of −660 Oe enabled us to gain deep insight into the transition metal doped magnetic semiconductor and to promote its full exploitation in magnetic-relevant applications.