Magnetism and phase transformation of Cu-Fe composite oxides prepared by the sol-gel route

Abstract

The Cu-Fe composite oxides were prepared by an epoxide assisted sol-gel route. The structural and magnetic properties of Cu-Fe composite oxides calcinated at different temperatures were determined by X-ray diffraction (XRD), Mössbauer spectroscopy measurements, and magnetic measurements. These results indicated that CuFe 2 O 4 was only formed as calcination temperature increased to 500• C, and a crystalline phase transformation from c-CuFe 2 O 4 to t-CuFe 2 O 4 occurred in elevating calcination temperature above it. All Cu-Fe oxides had ferromagnetic nature, and the significant superparamagnetic behavior was observed in the results of magnetic and Mössbauer spectroscopy measurements.