Morphotropic PMN–PT system investigated by comparison between ceramics and crystal

• Published in: Journal of the European Ceramic Society Vol. 25; no. 12; pp. 2509 - 2513
• Main Authors: Sebald, Gaël, Lebrun, Laurent, Guiffard, Benoît, Guyomar, Daniel
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 2005; Elsevier
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electrotechnical and electronic ceramics; Exact sciences and technology; Ferroelectric properties; Microstructure-final; Niobates, titanates, tantalates, pzt ceramics, etc; Perovskites; Physics; Piezoelectric properties; PMN–PT; Technical ceramics; Piezoelectric properties; Microstructure-final; Perovskites; PMN–PT; Ferroelectric properties; Lead oxide; Magnesium Niobium Lead Oxides Mixed; Perovskite type compound; Electrical properties; PMN-PT; Magnesium oxide; Lead titanates; Ferroelectric ceramics; Morphotropic phase boundary; Niobates; Experimental study; Solid solution; Oxide ceramics; Crystalline state; Niobium oxide; Microstructure; Comparative study; Electroceramics
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2005.03.092

Ferroelectric perovskite ceramics (1− x)Pb(Mg 1/3Nb 2/3)O 3– xPbTiO 3 were widely studied over the last 20 years, especially ceramics in the morphotropic phase boundary ( x = 0.3–0.4). More recently a new interest focuses on single crystals of the same composition grown either by Bridgman or flux technique. Giant electromechanical factor k 31, piezoelectric coefficient d 31, and field-induced strain S 3 were found ( k 31 > 0.85, d 31 > 1000 pC/N, S > 1%) making them very attractive for non-resonant applications. For resonant applications, despite their medium mechanical factor Q 31 these materials exhibit higher figure of merit Q 31 d 31 than the best PZT ( Q 31 d 31 > 3 × 10 5 for crystal, and Q 31 d 31 > 10 5 for the best PZT ceramics). However the origin of these outstanding properties is not well understood. The comparison between ceramics and crystal of the same composition (0.67PMN–0.33PT) towards the macroscopic properties was investigated. First the polarisability of materials was studied. The crystal shows an optimum poling electric field, which gives a maximum electromechanical coupling factor and piezoelectric charge d 31. It is believed that this surprising behaviour is due to the domain and phase engineering. The temperature and electric field stability was investigated for ceramics and crystal for different crystallographic cuts. A discussion is presented on the mechanical losses which are especially unstable.