Thermal expansion analysis and structural characteristics of the (Pb, Ca)TiO3 solid solutions from 150 to 570 K

Author(s)

F. R. Estrada ^[1] ; J. A. Eiras ^[2] ; D. Garcia ^[3]

Affiliation

^[1] Universidade Federal de S. Carlos. Departamento de Física. Grupo de Materiais Ferroicos - Brasil

^[2] Universidade Federal de S. Carlos. Departamento de Física. Grupo de Materiais Ferroicos - Brasil

^[3] Universidade Federal de S. Carlos. Departamento de Física. Grupo de Materiais Ferroicos - Brasil

• Document type: Journal article
• Source: Cerâmica; v. 63, n. 365, p. 116-121, 2017-03-00.

Abstract

Abstract Ceramic samples of lead modified calcium titanate (Pb1-xCaxTiO3) with calcium concentration between 0.24≤x≤0.55 were prepared and analyzed in order to determine the structural origin of the negative thermal expansion observed in this ferroelectric system. The Rietveld structural refinement method was used to assess the thermal evolution of the structural parameters using powder X-ray diffraction data collected between 150 and 570 K. Since the Pb1-xCaxTiO3 phase diagram and space groups are still unknown for the temperature range investigated, the structural analyses were based on adjustments of the refinement protocol. The results revealed the existence of a correlation between symmetry transitions and anomalies in the thermal expansion of the unit cell, being such transitions not necessarily of the ferroelectric-paraelectric nature. (AU)

• FAPESP's process: 08/04025-0 - Nanostructured multifunctional multiferroic materials: synthesis, properties, phenomenology and applications
• Grantee: José Antonio Eiras
• Support Opportunities: Research Projects - Thematic Grants