Static dielectric properties of ammonium tetrachlorozincate

Abstract

Single crystals of (NH₄)₂ZnCl₄ (AZC) were grown from aqueous solution of molar composition 1:1 of the components NH₄Cl and ZnCl₂. The static dielectric constants ε_a, ε_b, ε_c were measured in the normal, the incommensurate and the various commensurate phases of AZC. Whereas ε_c is not both ε_a and ε_b are generally influenced differently by the various phase transitions. Special emphasis is laid upon the circumstances which cause a peculiar anomaly of ε_a to appear at about 46 [ddot]C. The temperature dependences of the spontaneous respectively induced polarization in the 3C, (7/2)C and 4C phases are determined. The domain pattern of the 4C phase observed by polarization optical methods for virgin samples differs considerably from that of samples which have been heated up to the IC phase.