Crystal stractures and magnetic properties have been studied for magnetic oxde films prepared by a bias sputtering using garnet targets deposited on SiO2, GGG and sapphire substrates. The sputtered films were amorphous and those annealed at 700°C where crystallized. The films, which were sputtered at zero bias, were poly-crystalline garnet structures on any substrates. When bias voltage was applied during sputtering, singlecrystalline garnet films were formed on GGG substrates and oriented orthoferrite films were grown on sapphire substrates.