Ferrite plating of Fe/sub 3/O/sub 4/ and Fe/sub 3-x/Ni/sub x/O/sub 4/ films at 100-200 degrees C

Ferrite plating of Fe/sub 3-x/Ni/sub x/O/sub 4/ (x=0-0.93) films in the temperature region T=120 degrees C-200 degrees C and in the pressure region P=15-20 kg/cm/sup 2/ was performed. A reaction solution and an oxidizing solution were supplied to a reaction cell by high-pressure pumps. A phase diagram for an iron oxide film was obtained for T=120 degrees C-180 degrees C and pH=4.0-7.6. Single-phase Fe/sub 3/O/sub 4/ (x=0) film grows only at T=180 degrees C and pH=6.0-7.6, with the alpha -Fe/sub 2/O/sub 3/ phase appearing outside the region. The solubility limit of Ni increases as the plating temperature increases, from x= approximately 0.3 at 80 degrees C to x=0.93 at 200 degrees C. All the films are polycrystalline with no preferential orientation, and the magnetization exhibits no definite anisotropy. The grain size of the films increases as x increases, reaching approximately 1 mu m at x=0.86.>