Ferroelectric and ferrimagnetic iron-doped thin-film BaTiO3: Influence of iron on physical properties

Structural and physical properties of ferroelectric and ferrimagnetic pulsed-laser deposition-grown thin-film BaFexTi1−xO3 with 0.5⩽x⩽0.75 (BFTO) are compared with those of BaTiO3 (BTO) films deposited under identical conditions. Fe leads to lattice expansion and deterioration of the crystalline quality in the as-prepared films. Signatures of the paraelectric–ferroelectric phase transition in lattice parameters, resistivity, and capacitance tend to be suppressed in BTO films, but are clearly distinguished in the presence of Fe. While strain elevates TC above bulk values in thin-film BTO to ∼200 °C, Fe doping entails further increases of TC up to ∼320 °C. Current versus voltage measurements demonstrate that Fe converts n-type BTO into p-type BFTO. Fe doping brings about ferrimagnetic ordering with a Néel temperature above 450 °C.