Preparation and characterization of nanoparticulate CoFe2O4 thin films by the sol-gel method

Co-ferrite thin films have been fabricated on Coming glass substrates by a chelating sol-gel process. Structural and magnetic properties of the films have been studied as a function of annealing temperature using an X-ray dif fraction (XRD) and a vibrating sample magnetometer. XRD results revealed th at most of the Co-ferrite grains were randomly oriented. Rapid annealing (R A) and standard annealing (SA) processes were used for the variation of hea t treatment and the characteristic comparison. Coercivity was changed with the thermal condition and the magnetisation increased with the soaking time . With prolonged soaking time, however, the coercivity decreased. due to th e diffusion of cations from the glass substrate. RA in the preparation of C o-ferrite thin films was effective for preventing interdiffusion at interfa ces and for forming a single phase in the case of reduced soaking time. A y ttria stabilized zirconia (YSZ) buffer layer between the Co-ferrite layer a nd the substrate was effective for improving the magnetic properties of the films at higher temperatures. It was observed that Co-ferrite thin films w ere composed of grains typically 35 nm in size and their rms roughness was approximately 1.3 nm. The saturation magnetization of the thin films by sub jected to rapid annealing at 900 degrees C for 150 seconds was 400 emu/cm(3 ) and the coercivity of the films was approximately 3000 Oe.