A wide range of thin ferrite films has been prepared by a chemical‐deposition process. Alcoholic solutions of ferric nitrate and other metal nitrates were combined in necessary proportions to yield stoichiometric ratios of the desired ferrites, which were then deposited on substrates. Firing the coated substrates between 900–1100°C in a controlled atmosphere resulted in spinel or garnet ferrite formation. Magnetic properties were evaluated at X band by cavity‐resonance measurements. Ferrimagnetic linewidths obtained ranged between 125 and 1950 Oe. Crystal structure and composition were verified by x‐ray diffraction analysis. Experimental data are given. A nickel film was measured in an experimental resonance isolator in the 35‐Gc region resulting in a maximum reverse to forward loss ratio of 22.7 to 1. Data and results obtained suggest applications in millimeter and submillimeter ferrite devices.