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Temperature dependence of microwave loss in antiferroelectric squaric acid crystal

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Title Temperature dependence of microwave loss in antiferroelectric squaric acid crystal
 
Creator Upadhyay, Trilok Chandra
 
Subject Antiferroelectrics
Anharmonic interactions
Dielectric
Loss tangent
 
Description 119-124
A model of pseudospin for layers 1 and 2 of squaric acid (SQA) crystal proposed by Li and Qin, Ferroelectrics, 82 (1988), 69 has been modified to include pseudospin-phonon interaction and cubic and quartic phonon anharmonic interactions. With the help of double-time temperature dependent Green's function method and modified Hamiltonian, expressions for antiferroelectric soft mode frequency, dielectric constant and loss have been evaluated. By fitting model values of physical quantities in the theoretical expressions, temperature dependences of soft mode frequency and loss have been calculated. In the microwave frequency range, an increase in frequency is followed by increase in loss. The loss decreases with increase in temperature for SQA crystal in its paraelectric phase. This shows Curie-Weiss behaviour of the dielectric tangent loss. Theoretical results are compared with experimental results of Muser [Proc. 6th Int'l Meeting on Ferroelectricity, Kobe (1985)], Maier et al. [Phys Status Solidi (b) 89, (1978)], and Samara and Semmingsen [J Chem Phys 71 (3) (1979) 1401] which show a good agreement.
 
Date 2009-02-18T11:55:38Z
2009-02-18T11:55:38Z
2009-02
 
Type Article
 
Identifier 0019-5596
http://hdl.handle.net/123456789/3184
 
Language en_US
 
Publisher CSIR
 
Source IJPAP Vol.47(2) [February 2009]