Cole-Cole Analysis of a New Lead Free NaNbO3-Sr0.5NbO3-LiNbO3Ferroelectric Relaxor

Autor:	J.-L. Dellis, S. I. Raevskaya, I. P. Raevsky, L. A. Reznitchenko
Rok vydání:	2005
Předmět:	Permittivity Materials science Nuclear magnetic resonance Condensed matter physics Electrical resistivity and conductivity Relaxation (NMR) Dielectric Activation energy Condensed Matter Physics Ferroelectricity Critical exponent Electronic Optical and Magnetic Materials Cole–Cole equation
Zdroj:	Ferroelectrics. 318:169-177
ISSN:	1563-5112 0015-0193
Popis:	Dielectric response of (NaNbO3)0.65-(Sr0.5NbO3)0.325-(LiNbO3)0.025 lead-free relaxor ceramic has been studied as a function of frequency over a wide range of temperatures. The relaxor behaviour was evident from the diffused and frequency-dependent dielectric permittivity maximum together with Vogel-Fulcher-like frequency shift of permittivity maximum temperature (T m ). Analysis of the Cole-Cole plots as function of the temperature allowed us to elucidate two different dielectric relaxations and the appearance of a dc conductivity contribution above 100°C. The LF relaxation and dc conductivity have the same activation energy. The HF relaxation is characterised by a distributed relaxation time spectrum described by the well-known Cole and Cole expression. On cooling from 170°C a critical exponent α exhibits a pronounced increase from almost 0 (a Debye-like relaxation) to 0.8 in the vicinity of the Vogel-Fulcher temperature and saturates at lower temperatures. Such behaviour of α corresponds to the broadeni...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::4fcd3eb6cc0cadbda9f1dd4959c9c3d6 https://doi.org/10.1080/00150190590966324 Zobrazit plný text záznamu