Abstract
Barium ferrite films were prepared by r.f. diode sputtering on AlN underlayers, and their crystal orientation and magnetic properties were investigated. The AlN underlayers, well oriented in c-axis, with the thickness of around 3000-5000Å were deposited at room temperature. On that AlN underlayer with the thickness of 5000Å, the barium ferrite films were deposited. As the deposited barium ferrite films were not crystallized, they were post-annealed at the temperatures between 600°C and 900°C for 18 ks in air. When the film was annealed at 650°C or more, the hexagonal crystalline of barium ferrite was improved and its [001] axis slightly lying perpendicular to the film surface was recognized. The superior orientation of [001] axis may be presumed to be caused by the effect of AlN underlayer. However, its orientation was not perfectly uniaxial, because of the use of incomplete crystalline AlN underlayers. On the other hand, perpendicular magnetic anisotropy of the barium ferrite films deposited on the AlN underlayers was enhanced, owing to the effect of the underlayers.
