Dielectric, Elastic and Piezoelectric Properties of the Mixed Crystals System Na[K1-x(NH4)x]-Tartrate (0.90<x<1.0)

Dielectric, elastic and piezoelectric properties of the mixed crystals system, Na[K 1- x (NH 4 ) x ]C 4 H 4 O 6 · 4H 2 O (0.90< x <1.0), were systematically investigated. Temperature dependence of e a , e b and e c , elastic compliance coefficients s ' 11 , s ' 22 and s ' 33 , piezoelectric constants d 14 , d 25 and d 36 were measured for the crystals with x =1.0, 0.98, 0.96, 0.94, 0.92 and 0.90. Peculiar temperature dependence of d 25 was observed for the crystals with x =1.0, 0.98, 0.96, 0.94 and 0.92. An experimental formula was propsed to describe the temperature and concentration dependence of the piezoelectric constant d 25 .