Properties of Thin Ferroelectric Film with Different Electrodes.

The influence of different metallic and semiconducting electrodes on the properties of thin ferroelectric films is considered within the framework of the phenomenological Ginzburg-Landau theory. Allowing for the effect of charge screening in metals and semiconductors, the contribution of electric field produced by charges in the electrodes is included into the functional of free energy and, hence, to the Euler-Lagrange equation for film polarization. Application of variational method to this equation solution permitted the transformation of the free energy functional into a conventional type free energy with a renormalized coefficient before P2, the coefficient being dependent on the both characteristics of a film and an electrode. This opens a way to calculate the size effect by substituting the coefficient into the conventional formula of the phenomenological theory. A comparison with experimental data for Pt, Ir, IrO2, SrRuO3 has shown a good agreement between theory and experiment. [ABSTRACT FROM AUTHOR]