MAGNETIC-ORDERING IN AMORPHOUS OXIDES

The magnetic structure of radio frequency sputtered amorphous oxides has been investigated by magnetization and ferromagnetic resonance techniques. Samples of Bi2O3-Fe2O3 substituted with ABO3 (AB=BaTi, PbTi, PbZr) and MeO (Me=Cu, Ca, Zn) - type compounds have been studied. As-deposited samples are paramagnetic and samples annealed at high temperatures show a ferrimagnetic character possibly due to the formation of magnetically ordered clusters. Key accomplishments of our studies are: (i) samples with nonmagnetic ABO3 show a record room temperature magnetization, (ii) films containing oxides of zinc, copper, or calcium are anisotropic amorphous magnets with a large uniaxial or planar anisotropy, (iii) the nature and composition of ordered clusters in some samples have been inferred from magnetic characterization of the films, and (iv) a similar ferrimagnetic character is observed in amorphous samples sputtered at high temperatures.