Abstract
The dynamical process for dipolar ordering in ferroelectric crystals of tris-sarcosine calcium chloride has been studied through the dielectric and electron paramagnetic resonance anomalies in the critical region, for which a collective fluctuation of local-order parameters is considered to be responsible. Although different aspects of the phase transition are dealt with, these anomalies provide complementary information about the quasi-one-dimensional mode of order parameters. Induced by B2u soft phonons in the para-electric phase, it may be regarded as a condensate stabilized by the short-range correlation among constituent order parameters. In real crystals where randomly distributed defects violate the translational symmetry of the lattice, the condensate at long wavelengths either may be pinned or may slide free from defects. Depending on the defect density in sample crystals, the anomalies were observed as composed of these two condensate modes characterized by distinct frequencies. The significance of lattice defects for the polarization fluctuation at the ferroelectric phase transition is discussed.