Microstructural properties of (112¯0)-oriented hematite-ilmenite solid solution films

Ilmenite-hematite solid solution (Fe2-xTixO3) is one of the candidates for high-temperature magnetic semiconductors. Well-crystallized and epitaxially formed Fe2-xTixO3 films on α-Al2O3 (112¯0) single-crystalline substrates were tried to fabricate by using reactive sputtering technique. The detailed structural properties of (112¯0)-oriented epitaxial Fe1.4Ti0.6O3 films were analyzed by using transmission electron microscope (TEM). The films showed large magnetization and typical semiconductive conduction at room temperature. However their anisotropic properties were rather small than expected, though the films had good crystallinity with preferred orientation. The TEM observations clearly revealed that the (112¯0)-oriented Fe1.4Ti0.6O3 films on α-Al2O3(112¯0) were partly composed of the (0001)-oriented grains. Formation of the (0001)-oriented grains could reduce the anisotropic properties of the (112¯0)-oriented films.