THE PHYSICAL-PROPERTIES OF K2ZN1-XCOXCL4 MIXED-CRYSTAL

K2ZnCl4 and K2CoCl4 both belong to the Rb2ZnCl4 group with incommensur ate phase. In this study K2Zn1-xCoxCl4 mixed crystals were grown by Cz ochralski method. We expect that Co ions act not as impurities, but as cations centered in tetrahedra. While the dielectric anomaly at the c ommensurate-incommensurate (C-INC) phase transition is smeared out wit h the increasing impurities, for example, as in (Rb1-xKx)(2)ZnCl4, we observed in our system K2Zn1-xCoxCl4 distinct anomalies at every measu red concentration x (x = 0, 0.001, 0.01, 0.1, 0.3, 0.5, 0.7). The dope d Cb ions do not induce the destruction of the multisoliton lattice du e to random-phase pinning in this system and not destroy the long-rang e order, but the increase of x contributes to increase of T-c.