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IJPAP Vol.45(02) [February 2007] >
| Title: | Temperature dependence of dielectric constant and loss tangent in layered antiferroelectric squaric acid crystal |
| Authors: | Upadhyay, Trilok Chandra |
| Keywords: | Dielectric constant
Pseudospin-phonon interaction
Antiferroelectric |
| Issue Date: | Feb-2007 |
| Publisher: | CSIR |
| IPC Code: | C30B |
| Abstract: | A model of pseudospin for layer type 1 and type 2 for squaric acid 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, loss and transition temperature have been evaluated. By fitting model values of physical quantities in the theoretical expressions, temperature dependence of soft mode, dielectric constant and loss has been calculated in the vicinity of transition temperature. Theoretical results have been compared with experimental results of Muser (Ref. 6), Maier et al. ⁵ and Samara and Semmingsen (Ref. 9), which show a good agreement. |
| Page(s): | 157-162 |
| ISSN: | 0019-5596 |
| Source: | IJPAP Vol.45(02) [February 2007]
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