Low-temperature growth of c-axis-oriented Y-type hexagonal ferrite thin films by the polymeric precursor method

Well-crystallized Ba₂Zn₂Fe₁₂O₂₂ (Zn₂-Y) films with high c-axis oritentation were successfully formed on Ag substrates at low temperature by the polymeric precursor method. A precursor solution with stoichiometric Ba²⁺, Zn²⁺, and Fe³⁺ ions was deposited on the substrates by a dip-coating. The films were then heat-treated at temperatures ranging from 700 to 900°C. The crystallization process of c-axis-oriented Zn₂-Y films occurred at the considerably low temperature of 750°C, though a small amount of spinel oxides contaminated them. The films had hexagonal grain structures which were developed by increasing the heat-treatment temperature. Magnetization curves of the Zn₂-Y film heated at 900°C clearly indicated that the film had large in-plane magnetic anisotropy and had small in-plane coercivity.