Incomplete ferroelectricity in SrTi<Superscript> 18</Superscript>O<Subscript> 3</Subscript>

Motivated by recent experiments demonstrating suppression of ferroelectricity with pressure in SrTi<Superscript>18</Superscript>O<Subscript>3</Subscript>, the dynamics of the phase transition mechanism are reinvestigated within a nonlinear polarizability model. For temperatures far above the phase transition polar micro domains are formed which increase in size with decreasing temperature to freeze out at T<Subscript>c</Subscript> without forming long range order. Experimentally, soft mode dynamics are simultaneously observed, evidencing that displacive and order/disorder features coexist. In the ferroelectric phase both components persist whereby an incomplete and inhomogeneous ferroelectric state is formed. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2006