Relaxation dynamics of disordered Ising-like models

Being the model of critical phenomena in many different objects an Ising model compels the attention during many years. Within the framework of quasispin models successful efforts are undertaken to describe a variety of ferroelectric phenomena in different ferroelectric crystals. In this paper we study the kinetics of Ising and Mitsui models (within master equation [1] approach) in order to describe the dynamic properties of partially deuterated ferroelectrics of order-disorder type. We develop a two-site cluster approximation (TCA) for strong short-range interactions present in such crystals. The long-range interactions will be taken into account within the mean field approximation.