OXYGEN-PRESSURE DEPENDENCE OF LASER-DEPOSITED BARIUM FERRITE FILMS ONLLC(111)

Hexagonal Barium Ferrite thin films with perpendicular anisotropy were successfully fabricated on the (111) surface of large lattice constan t (LLC) garnet substrates using pulsed laser deposition. Oxygen pressu re plays a crucial role in determining film growth characteristics. Th e film grown at 50 mTorr oxygen pressure has a clear hexagonal structu re but is very weakly crystallized due to the lack of oxygen. Increasi ng the oxygen pressure enhances both crystallization and the in-plane c-axis oriented crystal growth, hence it reduces the perpendicular ani sotropy. The optimum pressure is about 180 mTorr which gives a crystal lized film with predominantly perpendicular c-axis orientation. The se nsitive dependence of film structure on processing gas pressure shown in this work is important in controlling film properties such as aniso tropy and grain size for different applications.