ORIENTATIONAL ORDERING IN SPATIALLY DISORDERED DIPOLAR SYSTEMS

This Letter addresses basic questions concerning ferroelectric order i n positionally disordered dipolar materials. Three models distinguishe d by dipole vectors that have one, two, or three components are studie d by computer simulation. Randomly frozen and dynamically disordered m edia are considered. It is shown that ferroelectric order is possible in spatially random systems, but that its existence is very sensitive to the dipole vector dimensionality and the motion of the medium. A ph ysical analysis of our results provides significant insight into the n ature of ferroelectric transitions.