Preparation and Magnetic Properties of CoCrFeO₄ Nanocrystals

Abstract

CoCrFeO4 nanocrystals were synthesized using a sol−gel method. The specimen had an average grain size of 8.1 nm. The zero-field-cooled and field-cooled curves showed a superparamagnetic transition occurring at a blocking temperature of TB ≈ 249 K. The temperature dependence of the saturation magnetization showed that Bloch's law holds but with a Bloch exponent lower than the bulk value. These results imply that the magnetic behavior of nanoparticles is richly dependent on the surface and the interface.