Preparation of nickel and Ni-Zn ferrite films by thermal decomposition of metal acetylacetonates

Nickel and Ni-Zn ferrite (Ni_1–x Zn _x Fe₂O₄) films were prepared on various substrates (quartz glass, MgO single crystal, etc.) by thermal decomposition of metal acetylacetonates (Ni (acac)₂ · 2H₂O, Zn (acac)₂ · 2H₂O and Fe (acac)₃). Typical decomposition and heat treatment conditions for obtaining a single phase of NiFe₂O₄ film were as follows: evaporation temperature of Ni-Fe complexes: 230°C, the mole concentration of Fe (acac)₃,R (%) = Fe (acac)₃/(Fe (acac)₃ + Ni (acac)₂ · 2H₂O) = 33, substrate temperature: 330 to 550° C, and heat treatment of the as-grown film: 800 to 1000° C, 1 h. Ni_1–x Zn _x Fe₂O₄ films were obtained by controlling the compositionR in Ni-Fe complexes and the evaporation temperature of Zn (acac)₂ · 2H₂O. The Ni-Zn ferrite film at the compositionx = 0.37 (Ni_0.63Zn_0.37Fe₂O₄) gave the maximum saturation magnetization _s = 60 emu g^–1 and the coercive forceHc 25 Oe. These films showed a magnetic anisotropy which makes the magnetization easy parallel to film surface.