Composition dependence of the magnetic properties of CoFe2O4/CoFe2 composite nano-ceramics

CoFe2O4/CoFe2 composite nano-ceramics with varying composition ratios were synthesized using a reduction reaction and spark plasma sintering. The compositions and particle sizes of the ceramics were then characterized using X-ray diffraction, and the mass ratios were quantitatively determined via thermal-gravity analysis. The magnetic property characteristics indicate that the coercivity decreased significantly with an increase in the soft-magnetic CoFe2 content, while the saturation magnetization drastically increased. In addition, a characterization of the Henkel plots showed a clear enhancement of the inter-phase exchange coupling when the number of soft-magnetic CoFe2 nano-particles was increased. Enhanced exchange coupling at the interface between the soft-magnetic and the hard-magnetic phases is critical for the occurrence of exchange-spring behavior, which has potential applications in the field of information technology.