Phase Transitions in the Modified Weiss Model.

In a recent paper, the modified model by P. Weiss was applied to ferroelectrics. Typical ferroelectric properties could be simulated. A further generalization of the Weiss model is the assumption of a power law feedback with an exponent κ between the polarization of the permanent dipoles and the local field. The Weiss model is included for the exponent κ = 1 and we obtain a second-order type phase transition. For values κ > 1 the simulations yield first-order type phase transitions whereas we obtain diffusive-type phase transitions for values κ < 1. [ABSTRACT FROM AUTHOR]