Temperature-driven structural transformations in Ca/Ti- and Ba/Ti-doped BiFeO3

• Published in: Materials letters Vol. 254; pp. 305 - 308
• Main Authors: Khomchenko, V.A., Karpinsky, D.V., Zhaludkevich, D.V., Latushka, S.I., Franz, A., Sikolenko, V.V., Nekludov, K.N., Dubkov, S.V., Silibin, M.V., Paixão, J.A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2019; Elsevier BV
• Subjects: BiFeO3; Bismuth ferrite; Crystal structure; Displacements (lattice); Electric polarization; Ferroelectric materials; Ferroelectricity; Magnetic properties; Materials science; Multiferroics; Neutron diffraction; Parameters; Phase transitions; BiFeO3; Neutron diffraction; Crystal structure; Multiferroics
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2019.07.091

•High-temperature neutron diffraction study of Ca/Ti- and Ba/Ti-doped BiFeO3 was performed.•The heating-induced R3c ↔ Pnma (Ca/Ti) and R3c ↔ Pm3-m (Ba/Ti) phase transitions were revealed.•The temperature-driven changes in structural parameters of the ferroelectric phase were described. The structural parameters of the Bi0.85AE0.15Fe0.85Ti0.15O3 (AE = Ca and Ba) multiferroics have been determined using variable temperature neutron powder diffraction. The compounds adopt the polar rhombohedral R3c structure near room temperature and undergo phase transitions into either the nonpolar orthorhombic Pnma (AE = Ca) or cubic Pm3-m (AE = Ba) structures on heating. In the ferroelectric phase, a temperature-driven lattice expansion is accompanied by both a diminishing of the off-center ionic displacements (thus resulting in a decrease in the spontaneous electric polarization) and a reduction in the magnitude of the antiphase oxygen octahedra tilting. Being largely different for the materials under study, the latter parameter is supposed to specify the dissimilarity in their magnetic properties.