• Correlation between deformation bleaching and mechanoluminescence in coloured alkali halide crystals

    • Fulltext

       

        Click here to view fulltext PDF


      Permanent link:
      http://www.ias.ac.in/article/fulltext/pram/054/02/0287-0303

    • Keywords

       

      Deformation bleaching; colour centres; alkali halides.

    • Abstract

       

      The present paper reports the correlation between deformation bleaching of coloration and mechanoluminescence (ML) in coloured alkali halide crystals. When the 𝐹-centre electrons captured by moving dislocations are picked up by holes, deep traps and other compatible traps, then deformation bleaching occurs. At the same time, radiative recombination of dislocation captured electrons with the holes gives rise to the mechanoluminescence. Expressions are derived for the strain dependence of the density of colour centres in deformed crystals and also for the number of colour centres bleached. So far as strain, temperature, density of colour centres, 𝐸a and volume dependence are concerned, there exists a correlation between the deformation bleaching and ML in coloured alkali halide crystals. From the strain dependence of the density of colour centres in deformed crystals, the value of coefficient of deformation bleaching 𝐷 is determined and it is found to be 1.93 and 2.00 for KCl and KBr crystals, respectively. The value of $(D + \mathcal{X})$ is determined from the strain dependence of the ML intensity and it is found to be 2.6 and 3.7 for KCl and KBr crystals, respectively. This gives the value of coefficient of deformation generated compatible traps $\mathcal{X}$ to be 0.67 and 1.7 for KCl and KBr crystals, respectively.

    • Author Affiliations

       

      B P Chandra1 M Ramrakhiani1 P Sahu2 A M Rastogi2

      1. Department of Postgraduate Studies and Research in Physics and Electronics, Rani Durgavati University, Jabalpur 482 001, India
      2. Department of Physics, Government Maharaja College, Chhatarpur 471 001, India
    • Dates

       
  • Pramana – Journal of Physics | News

    • Proceedings of the International Workshop/Conference on Computational Condensed Matter Physics and Materials Science
      (IWCCMP-2015)

      Posted on November 27, 2015

      Guest Editors: Anurag Srivastava, C. S. Praveen,
      H. S. Tewari

© 2017 Indian Academy of Sciences, Bengaluru.