Influence of impurity on soliton density near the incommensurate-ferroelectric phase transition in (Rb_{1 - x}K_x)₂ZnCl₄:Mn²⁺ mixed crystals

Abstract

The temperature and impurity-concentration dependence of the soliton density has been investigated near the lock-in transition from the incommensurate phase to the ferroelectric one in (Rb_{1 - x} )K _x )₂ZnCl₄ mixed crystals doped with paramagnetic probe Mn^{2 +}. The soliton density n_s was derived from EPR data by the evaluation of the sharp “commensurate” lines (so-called C-lines) intensities and was calculated from dielectric data. Comparison of the results of radiospectroscopic and dielectric experiments indicates that below the lock-in transition temperature T_c there is no direct proportionality between the dielectric tail and the excess soliton density.