Ginsburg-Landau theory

A simple quantitative model, with no adjustable parameters, is developed for the finite size effect of ferroelectric particles on the Curie transition temperature. As the size of ferroelectric particles decreases, the Curie temperature decreases. Based on our model for lattice contraction and the Landau-Ginsburg-Devonshire (LGD) phenomenological theory, size effects on Curie temperature of lead zirconate titanate PbZri. Ti Oj (PZT, x > 0.6) are considered. It is shown that Curie temperature of PZT (x > 0,6) decreases with decreasing particle size. The predictions of our equation are in agreement with the experimental results. [Pg.377]

Recently, a quantitative model for the size-dependent Curie temperature has been established based on mechanic and thermodynamic considerations using the Landau-Ginsburg-Devonshire (LGD) phenomenological theory by equalizing free energies of the ferroelectrics and paraelectrics phases [1-4],... [Pg.377]

The well-known Landau-Ginsburg-Cochran-Anderson theory is a phenomenological approach. Of the first-principle theories, just one, the vibronic theory of ferroelectricity (e.g., see [1,51]), is consistently based upon electronic structure and chemical nature of the respective compounds. [Pg.707]