Diffuse phase transition in ferroelectrics with mesoscopic heterogeneity: Mean-field theory
- 1 May 1997
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 55 (18), 12067-12078
- https://doi.org/10.1103/physrevb.55.12067
Abstract
The diffuse phase transition in ferroelectrics with mesoscopic heterogeneity has been discussed within the context of a superparaelectric model by using the Ginzburg-Landau formalism. In the Curie region ferroelectrics with mesoscopic heterogeneity are treated as 'superparaelectrics' consisting of a mass of polar clusters, each of which has Ising character. Based on the mean-field theory, the influence of the finite-size effects of polar clusters on their structural instability has been discussed by considering a coherent lattice coupling between two structurally different regions. In particular, we have analytically derived the explicit solutions of the distribution of local polarizations. In turn, the processes of polar nanophase precipitation and coarsening have been also discussed in conjunction with the local chemical or structural inhomogeneity. Moreover, we have also analyzed the relationship between the local polarization distribution and the static dielectric susceptibility in ferroelectrics with the nanometric scale heterogeneity. The width of the Curie region is dependent upon the distribution of the sum of localized correlation length, which reflects the size distribution of heterogeneity. The presented analysis reveals that the diffuse phase transition is closely associated with the existence of nanometric polar clusters and their physical size distribution. Intriguingly, our theoretical results bear a very close resemblance to most experimental observations.Keywords
This publication has 63 references indexed in Scilit:
- Size-induced diffuse phase transition in the nanocrystalline ferroelectricPhysical Review B, 1995
- Ferroelectric thin films with polarization gradients normal to the growth surfaceApplied Physics Letters, 1995
- Charge pumping and pseudopyroelectric effect in active ferroelectric relaxor-type filmsPhysical Review Letters, 1992
- Orientational glassesAdvances in Physics, 1990
- Dipole glass and ferroelectricity in random-site electric dipole systemsReviews of Modern Physics, 1990
- Nanostructural-Property Relations in Complex Lead PerovskitesJapanese Journal of Applied Physics, 1990
- Ferroelectrics with diffuse phase transitionFerroelectrics, 1984
- Temperature‐Stable Dielectrics Based on Chemically Inhomogeneous BaTiO3Journal of the American Ceramic Society, 1984
- Ferroelectric Phase Transition in MicrocrystalsPhysical Review Letters, 1982
- The growth of Ba1-xSrx TiO3 crystals by a KF flux methodFerroelectrics, 1975