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The Polarised Raman Spectra of Ferroelectric and Non‐Ferro‐electric Potassium Lithium Niobate
Author(s) -
Siapkas D.,
Clarke R.
Publication year - 1974
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220620103
Subject(s) - curie temperature , raman spectroscopy , ferroelectricity , lithium niobate , dielectric , materials science , soft modes , lithium (medication) , condensed matter physics , potassium niobate , crystal (programming language) , nuclear magnetic resonance , analytical chemistry (journal) , chemistry , optics , physics , optoelectronics , ferromagnetism , medicine , chromatography , endocrinology , computer science , programming language
The polarised Raman spectra of two potassium lithium niobate compositions are presented. The first, a nearly stoichiometric ferroelectric version, K 5.9 Li 3.8 Nb 10 O 30 , exhibits a strongly temperature dependent A 1 ( z ) spectrum near the Curie point. This is held to be indicative of soft mode behaviour. The relationship between structural, dielectric and Raman measurements in this material is discussed. Measurements of the integrated intensity of the A 1 ( z ) modes, as a function of temperature, are presented and an estimation of the room‐temperature spontaneous polarisation is deduced. The A 1 ( z ) modes persist for tens of degrees above the Curie point indicating that there are regions of non‐zero polarisation within the crystal above the Curie point. No temperature dependence of the A 1 ( z ) mode frequencies is observed in K 5.0 Li 2.4 Nb 10 O 30 , a closely related non‐ferroelectric composition.