De, Dilip Kumar and Yerima, J. B. (2008) 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, 3 (12). pp. 306-313. ISSN 1992 - 1950
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Abstract
The energy Eo by which one of the three Jahn-Teller potential wells becomes lower than the other two in Cu2+:ZnTiF6.6H2O single crystal at phase transition temperature, Tcl are determined at temperatures below Tcl for different Cu2+ concentrations from the electron paramagnetic resonance (EPR) spectra. As the sample is cooled, it is found that for high Cu2+ concentration, Eo increases 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, Tcl is 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 Tcl with Cu2+ impurity concentration is presented. Eo is 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 nonexistence of phase transition in some compounds like CuTiF6.6H2O and ZnSiF6.6H2O belonging to the same class with ZnTiF6.6H2O.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ZnTiF6.6H2O, Cu2+, Jahn-Teller potential. |
| Subjects: | Q Science > Q Science (General) Q Science > QC Physics |
| Divisions: | Faculty of Engineering, Science and Mathematics > School of Physics |
| Depositing User: | Mrs Hannah Akinwumi |
| Date Deposited: | 12 Apr 2015 19:48 |
| Last Modified: | 12 Apr 2015 20:08 |
| URI: | http://eprints.covenantuniversity.edu.ng/id/eprint/4896 |
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