CHARACTERIZATION OF THE MAGNETIC-PROPERTIES AND TRANSPORT MECHANISMS OF COXFE3-XO4 SPINEL

CoxFe3-xO4 spinels were synthesized at 1100 degrees C in air and their phases were investigated by XRD. In the IR spectra of these samples, the stretching vibration of tetrahedral group was observed at 583cm(-1), which means that the tetrahedral structure was not influenced by the concentration of Co ion. The cation distribution determined by Mossbauer spectroscopy is closely related to the lattice parameter as well as magnetic properties. From the measurements of the magnetic moment, it has been known that the arrangement of magnetic moment between tetrahedral(A) and octahedral(B) site is canted in this spinel. The n-type and p-type conductions were observed in the samples with x<1.0 and x=1.2, respectively, showing that p-type to n-type transition occurred at 1140K in the sample of x=1.0. The n-type and p-type conductions are due to the formation of Fe2+ ion and Co3+ ion forming Co2++Co4+ exciton in B site.