ORIENTED BARIUM HEXAFERRITE FILMS GROWN ON AMORPHOUS SUBSTRATES

Pulsed laser deposition has been investigated as a means to obtain c-axis oriented barium hexaferrite films on amorphous substrates. Three film growth approaches were used: (1) deposition from a bulk polycrystalline barium hexaferrite target directly onto fused quartz substrates; (2) post-annealing of the as-deposited films; and (3) deposition onto a zinc oxide (ZnO) buffer layer on fused quartz, which was also grown using PLD. The first approach yielded four phases: amorphous, Fe3O4 (magnetite), alpha-Fe2O3 (hematite), and BaFe12O19 (barium hexaferrite). Films grown at temperatures greater than about 750-degrees-C and 100 mTorr were single-phase barium hexaferrite with texture, but exhibited no significant c-axis orientation. However, annealing the amorphous films at 700-degrees-C for 6 h produced a c-axis oriented barium hexaferrite film. From approach (2), X-ray diffraction revealed that the films of ZnO deposited on fused quartz at 600-degrees-C and 200 mTorr were c-axis oriented, and that subsequent deposition from the barium hexaferrite target at 750-800-degrees-C and 300 mTorr led to the growth of a c-axis oriented barium hexaferrite film. The saturation magnetization, magnetic anisotropy field and ferrimagnetic resonance linewidths of these films are in agreement with bulk values found in the literature.