Dependence of temperature variation of the Jahn-Teller potential well splitting and phase transition temperature in CuxZn1-xTiF6.6H2O crystals on Cu2+ ion concentration, x

International Journal of Physical Sciences

Dilip K. De¹ 

关键词: ZnTiF6.6H2O;    Cu2+;    Jahn-Teller potential.;   

DOI  :  

学科分类：物理（综合）

来源: Academic Journals

【 摘 要 】

The energy Eoby which one of the three Jahn-Teller potential wells becomes lower than the other two in Cu2+:ZnTiF6.6H2Osingle crystal at phase transition temperature, Tclare determined at temperatures below Tclfor different Cu2+concentrations from the electron paramagnetic resonance (EPR) spectra. As the sample is cooled, it is found that for high Cu2+concentration, Eoincreases below Tcl at a rate much slower than that for low concentration and over a much broader temperature range. With the increase of Cu2+concentration, Tclis found to decrease significantly. These findings appear to have a bearing on the monoclinic distortion that proceeds in this system below Tcl. Qualitative explanation of the decrease of Tclwith Cu2+impurity concentration is presented. Eois negligibly small for Cu2+concentrations above certain limits means that the barrier height is also vanishing for such Cu2+concentrations that is, phase transition of host lattice ceases. This is likely the reason for non-existence of phase transition in some compounds like CuTiF6.6H2O and ZnSiF6.6H2O belonging to the same class with ZnTiF6.6H2O.

【 授权许可】

CC BY