Relaxation processes of off-center impurities in KTN:Li crystals

Gabriel Bitton*, Yuri Feldman, Aharon J. Agranat

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

The dielectric and ferroelectric properties of K1-xLixTa1-yNbyO3 (KLTN) crystals as functions of temperature, frequency, and electric field are presented. Measurement of the polarization as a function of temperature indicates the existence of polarized microregions at temperatures well above the phase transition (PT) temperature. In the vicinity of the PT those microregions respond cooperatively and contribute to the observed macroscopic polarization. This cooperative behavior was also evident from dielectric relaxation measurements. Two relaxation processes were observed, one at high frequency and the other at low frequency. In both processes the relaxation time and the relaxation step (Δε) were found to increase as the PT temperature was approached. Those processes originate from movement of off-center ions in a multi-well potential. In the vicinity of the PT the correlation length of the host lattice is increased and the movements of the off-center ions become more and more correlated. The increased number of cooperatively relaxing ions increases the relaxation time and the relaxation amplitude.

Original languageAmerican English
Pages (from-to)362-367
Number of pages6
JournalJournal of Non-Crystalline Solids
Volume305
Issue number1-3
DOIs
StatePublished - Jul 2002

Bibliographical note

Funding Information:
This research was supported by grant no. 92-00361 from the United States–Israel Binational Science foundation (BSF), and by the Engineering Research Program of the US Department of Energy Office of Basic Energy Sciences under contract no. DE-AC05-00OR22725 with UT-Battelle, LLC.

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