Phase Transformations of Perovskite La-0.64(Ba1-xCax)(0.36)FeO3-delta Investigated by Mechanical Spectroscopy

Herein, perovskite La-0.64(Ba1-xCax)(0.36)FeO3-delta ( 0 <= x <= 0.4 $0 \leq x \leq 0.4$ ) samples are synthesized and investigated by X-ray diffraction and mechanical spectroscopy. The room-temperature structure of La0.64Ba0.36FeO3-delta is a mixture of orthorhombic and cubic phases. The structures of calcium-doped La-0.64(Ba1-xCax)(0.36)FeO3-delta are orthorhombic at room temperature. A modulus dip is observed above room temperature in La-0.64(Ba1-xCax)(0.36)FeO3-delta ( 0 <= x <= 0.4 $0 \leq x \leq 0.4$ ) samples. This corresponds to a phase transition from orthorhombic to rhombohedral structure with increasing temperature. The effect of oxygen nonstoichiometry on the room-temperature structure and phase transition is observed by mechanical spectroscopy.