A Green Function Estimation of Correction to Vegard's Law for isovalent Substitutional Defects in Alkali Halide Crystals |
| S. Datta Roy (Paul)a and S.K. Dasb a Department of Physics, Bethune College, Calcutta 700 006, India b Azad Physics Centre, Department of Physics, Maulana Azad College, Calcutta 700 013, India |
| Received: October 25, 1999; revised version January 25, 2000 |
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| A Green function method is developed for estimation of lattice parameter r(χ) of an AX-BX solid solution over entire composition range (χ=0 to 1). The r(χ) obtained in the present method is different from the value rV(χ) suggested by Vegard's law. We estimated the deviation from Vegard's law, r(χ)-rV(χ), over entire composition range for isovalent substitutional defect in alkali halide crystals. When compared to X-ray diffraction measurements, we find that the deviation is in correct direction, variation of r(χ) with χ is consistent with experiment and the overall agreement is fairly good considering the accuracy of the experiment. |
| DOI: 10.12693/APhysPolA.97.671 PACS numbers: 61.72.Bb, 61.82.Bg |