Complex exchange anisotropy behavior in Co3O4–Ni0.6Zn0.4Fe2O4 composite with different Co3O4 content

Co3O4–Ni0.6Zn0.4Fe2O4 composites with different Co3O4 content have been synthesized by the hydrothermal combining with sol–gel methods. Exchange bias and significant coercivity enhancement have been observed around and below Néel temperature, TN, of Co3O4 at certain Co3O4 content. Interestingly, the exchange anisotropy does not vanish at a much higher temperature of 200 K above TN. The exchange anisotropy behaves complexly with Co3O4 content at different temperatures, which suggest that exchange anisotropy are affected by not only the coupling between ferrimagnetic and antiferromagnetic phases but also the interfacial magnetic states.