Characterization and magnetic exchange observation for CoFe2O4-CoFe2 nanocomposite microfibers

The magnetic hard-soft CoFe2O4-CoFe2 nanocomposite microfibers have been synthesized by the sol-gel and partial reduction process, where CoFe2O4 ferrite is the hard phase with a grain size range from 43 to 62 nm and CoFe2 alloy the soft phase with grain sizes around 30 nm. These nanocomposite microfibers exhibit the magnetization behavior like a single phase magnetic material, and the magnetic exchange coupling effects are observed between the hard and soft phases. The specific saturation magnetization of CoFe2O4-CoFe2 nanocomposite microfibers shows an increase tendency with the increasing weight fraction of CoFe2, while the coercivity is consequently reduced. The nanocomposite microfibers have a maximum remanence 51.7 Am-2/kg when the phase contents of CoFe2 around 28 wt% and CoFe2O4 about 72 wt%.