Preparation and Characterization of (001) and (110)-Oriented Fe_(1.4)Ti_(0.6)O_3 Films

摘要

Thin films of ilmenite-hematite solid solution, Fe_(1.4)Ti_(0.6)O_3, were prepared on α-Al_2O_3 (001) and (110) single-crystalline substrates by reactive helicon plasma-sputtering technique. The oxide phases formed in the thin films and the degree of cation ordering in the ilmenite phase strongly depended on the preparation conditions. At the optimized preparation conditions, regardless of the substrate orientation, well-ordered Fe_(1.4)Ti_(0.6)O_3 films with R3 symmetry were epitaxially formed on the substrates. Large saturation magnetization at room temperature was observed in both (001)- and (110)-oriented films. The ordered Fe_(1.4)Ti_(0.6)O_3 films were ferrimagnetic semiconductors at room temperature. The (110)-oriented film had uniaxial in-plane magnetic and electric anisotropics, because Fe_(1.4)Ti_(0.6)O_3 had a magnetic easy plane and predominant conduction in the (001) crystallographic plane. The differences in magnetization and electrical resistivity curves between the (001)- and (110)-oriented films indicated the anisotropic nature of Fe_(1.4)Ti_(0.6)O_3.