Phase Transformations of Perovskite La0.64(Ba1−xCax)0.36FeO3−δ Investigated by Mechanical Spectroscopy

Herein, perovskite La 0.64 (Ba 1− x Ca x ) 0.36 FeO 3−δ () samples are synthesized and investigated by X‐ray diffraction and mechanical spectroscopy. The room‐temperature structure of La 0.64 Ba 0.36 FeO 3−δ is a mixture of orthorhombic and cubic phases. The structures of calcium‐doped La 0.64 (Ba 1− x Ca x ) 0.36 FeO 3−δ are orthorhombic at room temperature. A modulus dip is observed above room temperature in La 0.64 (Ba 1− x Ca x ) 0.36 FeO 3−δ () 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.