Characteristic temperatures and field effect in KTa1−x NbxO3 relaxor crystals seen via acoustic emission
Department of Applied Physics, The Hebrew University of Jerusalem - Jerusalem 91904, Israel
2 Graduate School of Pure and Applied Sciences, University of Tsukuba - Tsukuba, Ibaraki 305-8573, Japan
Accepted: 3 February 2012
-oriented KTa1−xNbxO3 (x=0.32) relaxor ferroelectric crystals have been studied by acoustic emission (AE) count rate in the temperature range from 200 K to 700 K. Burns temperature Td=620 K () and intermediate temperature T*=310 K () as well as both the tetragonal-cubic TT-C=259 K () and orthorhombic-tetragonal TO-T=243 K () phase transition temperatures have been clearly detected. T* is found to be influenced by an external DC electric field E: T* essentially decreases with a slope of approximately − 60 K·cm/kV accompanied with weakening in , as E enhances. The mechanisms of abnormal T*(E) and (T) dependences are discussed.
PACS: 77.80.Jk – Relaxor ferroelectrics / 77.80.B- – Phase transitions and Curie point / 43.40.Le – Techniques for nondestructive evaluation and monitoring, acoustic emission
© EPLA, 2012