Artículos de revistas
Nonequilibrium Thermodynamics And Quasielastic Light Scattering From Crystals. Ii. Piezoelectric Crystals
Registro en:
Physical Review B. , v. 22, n. 12, p. 6006 - 6012, 1980.
1631829
10.1103/PhysRevB.22.6006
2-s2.0-35949022426
Autor
Silva-Moreira A.F.
Institución
Resumen
The methodology described and utilized previously by the author, involving the use of nonequilibrium thermodynamics in the analysis of the spectrum of light scattered quasielastically by crystals, is applied to piezoelectric crystals. An additional thermodynamic variable, the electric polarization, is taken into account and assumed to be a relaxing variable. Solution of the resulting equations in the case of KH2PO4 leads, as expected, to the appearance of a polarization relaxation line in the spectrum. The spectrum is calculated for several values of the two relevant parameters: the polarization relaxation frequency and the ratio of C66 isothermal elastic constants at constant electric field and constant polarization. For a fixed polarization-relaxation frequency, it is found that as the ratio of elastic constants decreases (the characteristic behavior as the ferroelectric phase transition in KH2PO4 is approached), the intensity of the relaxation line increases at the expense of the Brillouin lines. In contrast with standard treatments of coupled modes in piezoelectric crystals, no adjustable parameters are involved in determining the spectrum. © 1980 The American Physical Society. 22 12 6006 6012