FERROELECTRIC BEHAVIOR OF KH2PO4 IN CRITICAL REGION

The temperature dependence of the hysteresis loops and the dielectric constant of KH2PO4 has been accurately determined in the neighborhood of the Curie temperature, Tc. No evidence has been found of a discontinous jump (indicative of a 1st order transition) in the spontaneous polarization at Tc. The critical exponents β = 0.50 ± 0.03, δ = 2.95 ± 0.10 and γ = 1.00 ± 0.05 have been determined. These values are closedto those found in other ferroelectric transitions (f.1. TGS) and are consistent with the mean field model predictions for the critical exponents. © 1969.