Dielectric Critical Phenomena in RbHSO₄

Abstract

Measurements of the spontaneous polarization are made for RbHSO₄. The results in the temperature range 0.1°C<T₀−T<100°C are well explained by using the elastic Gibbs function of G₁−G₁₀=(1⁄2)χP²+(1⁄4)ξP⁴+(1⁄6)ζP⁶ and χ=(4π⁄C)(T−T₀) with T₀=−8°C, C=144°C, ξ=7.2×10¹⁴ Jm⁵C⁻⁴ and ζ=4.2×10¹⁹ Jm⁹C⁻⁶. The value of δ defined by P∝E^1⁄δ at T₀ is obtained to be 3, the mean field value, in the range E≥∼200 V/cm.