Crossover from Ordinary Ferroelectric to Relaxor State: A Pre-Transitional Martensitic Transformation

• Published in: Ferroelectrics Vol. 339; no. 1; pp. 121 - 128
• Main Authors: Lente, M. H., Moreira, E. N., Garcia, D., Eiras, J. A., Neves, P. P., Doriguetto, A. C., Mastelaro, V. R., Lopes, L. P., Mascarenhas, Y. P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: London Taylor & Francis Group 01.01.2006; Taylor and Francis
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Dielectric loss and relaxation; Dielectric properties of solids and liquids; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Martensitic transformations; Materials science; Niobates, titanates, tantalates, pzt ceramics, etc; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; phase transitions; Physics; Raman spectroscopy; Relaxor; Raman spectra; Phase transformations; Martensitic transformations; Titanates; phase transitions; Relaxor; Raman spectroscopy; Relaxation time; Dielectric ceramics; Defects; Dielectric relaxation; Long range interaction; Domain structure; Zirconates
• ISSN: 0015-0193; 1563-5112
• DOI: 10.1080/00150190600738105

In this work we have investigated the nature of the crossover from the ordinary ferroelectric to the relaxor state in (Pb 1 − x Ba x )(Zr 0.65 Ti 0.35 )O 3 ceramics through dielectric and structural characterizations. Based on the martensitic transformation concepts, it is proposed that the continuous addition of isovalent-ions in the normal ferroelectrics decreases the long-range elastic interaction, thus transforming the domain patterns from a micrometer polydomain structure, through single domains, to nanometer polar "tweed" structures with glasslike behavior, which are in turn strongly driven by defects. The electrical interaction between these weakly-coupled polar-tweed structures leads to a wide spectrum of relaxation times, thus resulting in a dielectric relaxation process.