Kinetics of phase transitions in modulated ferroelectrics: Time-resolved neutron diffraction from Rb2ZnCl4

The kinetics of the ferroelectric phase transition between modulated phases in Rb2ZnCl4 at about 190 K has been investigated by time-resolved neutron scattering. Observing the time dependence of satellite spectra, it is found that the structural changes associated with the field-induced transformati on proceed on a millisecond time scale. Under the influence of fast cycling strong electric fields unusual non-equilibrium states are obtained which a re modulated in space as well as in time and characterised by the presence of internal mechanical strains.