Interactions in Dipole Systems: Model Simulations Using the Method of Local Fields

Abstract

Dielectric and ferroelectric properties are modeled taking into account dipolar interactions. Dipole systems consisting of permanent dipoles fluctuating thermally activated in double wells, of induced dipoles, and systems composed of permanent and induced dipoles are considered. Within the calculations the local field at each dipole is computed. For induced dipoles the local field solely and for permanent dipoles the local field and a Monte Carlo step determines the moment of the dipole. In an iterative procedure the polarization of the system is obtained. Among others the calculations yield hysteresis loops for the polarization with temperature dependent spontaneous and remanent polarizations, temperature and sample thickness dependent coercive fields, and a Curie-Weiss law for the susceptibility. The role of defects in the system is also considered as well as the role of the electrodes.