Microstructural investigations of barium ferrite longitudinal thin-film media

Crystalline barium ferrite films with in-plane magnetic anisotropy have been obtained by postdeposition annealing of amorphous sputtered films. The magnetic properties, the crystallographic texture, and the microstructure are very sensitive to the sputtering and postdeposition annealing conditions. It was found that both Hc and the grain size decrease with the addition of Co and Ti ions. However, an excessive amount of dopants leads to a loss in the in-plane anisotropy. Barium ferrite films produced by this technique contain physical voids or channels separating the grains which help to decrease the exchange coupling between grains.