Dielectric relaxation and piezoelectric coupling in the mixed proton-glass crystal K0.61(NH4)0.39H2PO4,

Abstract

Measurements of the dielectric permittivities in the mixed proton-glass crystal K0.61(NH4)0.39H2PO4 are reported from 20 Hz to 200.8 MHz and for fields along both the a and c axes. Between 14 and 50 K, the c-axis permittivity outside the piezoelectric-resonance range shows a temperature-dependent spread in relaxation times but cannot be fit accurately with the Cole-Cole formula. Strong piezoelectric resonance for a field along the c axis was observed in the region between 100 kHz and 10 MHz.