X-ray and dielectric studies of ferroelectric or relaxor phases in the Ca1-xNaxSn1-xNbxO3 system

• Published in: Solid state sciences 2005-03, Vol.7 (3), p.249-255
• Main Authors: AYDI, Abdelhedi, KHEMAKHEM, Hamadi, BOUDAYA, Chokri, SIMON, Annie, VON DER MÜHLL, Régnault
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Crystalline state (including molecular motions in solids); Dielectric properties of solids and liquids; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Material chemistry; Permittivity (dielectric function); Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Theory of crystal structure, crystal symmetry; calculations and modeling
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/j.solidstatesciences.2004.10.009

Ceramics with composition Ca1-xNaxSn1-xNbxO3 (0.85x0.96) were sintered in the temperature range 1200-1400 deg C. Dielectric properties of ceramics belonging to the whole composition domain were investigated in a broad range of temperatures (80-600 K) and frequencies (0.1-200 kHz). The thermal behavior of the dielectric permittivity suggests the existence of three phases: cubic-paraelectric, tetragonal-paraelectric and orthorhombic-ferroelectric or relaxor. The relaxor, or classical ferroelectric character, is dependent on the value of x. The symmetries of these three phases were investigated by X-ray diffraction study. The polarization state was checked by piezoelectric and pyroelectric measurements.