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Congruent Composition and Li‐Rich Phase Boundary of LiNbO 3
Author(s) -
O'BRYAN H. M.,
GALLAGHER P. K.,
BRANDLE C. D.
Publication year - 1985
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1985.tb15816.x
Subject(s) - curie temperature , phase boundary , composition (language) , phase (matter) , analytical chemistry (journal) , crystal (programming language) , chemical composition , mineralogy , materials science , crystal growth , crystallography , chemistry , thermodynamics , condensed matter physics , ferromagnetism , chromatography , linguistics , physics , philosophy , organic chemistry , computer science , programming language
The congruent composition of LiNbO 3 was determined precisely by correlating crystal growth compositions with the Curie temperatures of samples quenched from a melt before and after crystal growth and of various sections of crystals grown from that melt. The initial melt composition was determined by control of Li 2 CO 3 and Nb 2 O 5 contents. The melt compositions were varied from 47 to 49 mol% Li 2 O. The variation of T e with melt composition was found to follow T e = 9095.2 − 369.05C + 4.228C 2 , where C is mol% Li 2 O. High‐temperature DTA was used to determine T e with a precision of ±2°C. Above 1000°C the Li‐rich phase boundary was found to be a function of temperature by determining the weight gain after complete lithiation of congruently grown crystals. This boundary curves slightly toward lower Li 2 O content as temperature increases. The congruent composition of LiNbO 3 contains 48.45 mol% Li 2 O and has a measured Curie temperature of 1138°± 2°C.