Electrogyration effect of Rb₂ZnCl₄

Abstract

Electrogyration effect in the incommensurate phase of Rb₂ZnCl₄, which had been found to be optically active, was studied. Three plates, (010), (001) and (011), were subjected to HAUP measurements. On (010) and (001) plates no electrogyration effects were observed. On a (011) plate we observed that a linear electrogyration coefficient μ₄₁ takes place just above T_c . A quadratic coefficient μ₄₁ displays two remarkable peaks at a point 3°C below T_i and T_c . The upper peak of μ₄₁ is similar to the one observed in [N(CH₃)₄]₂ZnCl₄. It is of interest that both crystals belong to the same class in our new classification of optical activity.