PREPARATION AND CHARACTERIZATION OF THIN-FILMS OF M-TYPE BARIUM FERRITE ON MICROCRYSTALLINE CARBON SUBSTRATES WITH DIFFUSION BARRIER SUBLAYERS

Hexagonal barium ferrite films have been grown on microcrystalline carbon substrates for the first time and thermally oxidized SiO2/Si wafers using dc facing targets sputtering. Si3N4 and SiO2/Cr underlayers were effective in preventing carbon diffusion into the barium ferrite films during deposition at high temperatures (550-600-degrees-C). X-ray diffraction spectra showed that the c axis of the crystals are perpendicular to the film surface. The dispersion of the c axis (DELTAtheta50) was 2.5-degrees. The perpendicular coercivity varied from 860 to 1200 Oe and the saturation magnetization (M(s)) was about 300 emu/cm3. The delta M curves were negative in the in-plane direction and positive in perpendicular directions.