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

Herein, perovskite La0.64(Ba1−xCax)0.36FeO3−δ (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−δ is a mixture of orthorhombic and cubic phases. The structures of calcium‐doped La0.64(Ba1−xCax)0.36FeO3−δ are orthorhombic at room temperature. A modulus dip is observed above room temperature in La0.64(Ba1−xCax)0.36FeO3−δ (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. [ABSTRACT FROM AUTHOR]