Spinel-type (Fe_3-xM_xO₄, M=Fe, Co, Ni, and Zn) polycrystalline films were synthesized by ferrite plating at 25, 50, and 80°C from an aqueous solution of FeCl₂ + MCl₂ mixed with an oxidizing solution of NaNO₂ + CH₃COONH₄ + NH₃. For magnetite (Fe₃O₄), as the temperature was decreased from 80°C to 25°C, the pH of the reaction solution to obtain single-phase Fe₃O₄ increased from 6.8 to 8.4, and the maximum rate of film deposition decreased from 13.3 nm/min to 2.3 nm/min. For Fe_3-xM_xO₄, as the temperature was decreased from 90°C to 25°C, the ratio [x in film] / [x in reaction solution] increased from M = Co and Ni, while decreasing for M = Zn. This is explained by the dependence of the adsorption rate of M ions on the pH, which changes as the temperature changes. All the films had saturation magnetizations that compared favorably with those of bulk samples.