The contribution of piezoelectric effect to the observed dielectric anomaly was analysed in KDP single crystal in terms of simple damped harmonic oscillator model and were compared with the results of direct measurements made at 1 kHz and 10 kHz.
The polarization fluctuation associated with piezoelectricity was a resonance type and became overdamped below the domain freezing temperature.
The main part of the low frequency dielectric anomaly was shown to come from the piezoelectric effects and the real part of dielectric response was shown not to diverge in the vicinity of critical point but remain finite, whose magnitude could be estimated.