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Elastic anomalies and orientational glass transition in Na(CN) \(\)Cl \(\) mixed crystals. A Brillouin spectroscopic study

  • R.J. Jiménez Riobóo
  • K.-P. Bohn
  • J.K. Krüger

Abstract:

High performance Brillouin spectroscopy (BS) has been used to study the elastic properties (static and dynamic) of the orientational glassy state of Na(CN)xCl1-x samples \(\)). The temperature behaviour of the elastic properties reveals a more complex scenario for the orientational glass transition than generally believed. The shear elastic constant shows the well-known c 44 (T) anomaly, indicated by a minimum, found in other cyanide mixed crystals. The results obtained for the hypersonic attenuation are in clear contradiction with the dynamic character of the c 44 (T)-minimum. The temperature behaviour of the longitudinal elastic constant c11 of very dilute \(\)Na(CN)xCl1-x samples shows two striking features: i) Similar to the anomalous temperature behaviour of c 44 (T), lowering the temperature c 11 (T) first decreases, goes through a minimum and then rises again. The minimum takes place at a temperature above the temperature, \(\), where c 44 (T) reaches its minimum value. ii) A kink-like anomaly of c 11 (T) is observed at lower temperatures. This second anomaly is similar to the classical one observed in canonical glasses at their glass transition temperature \(\).

PACS. 62.20.Dc Elasticity, elastic constants - 64.70.Pf Glass transitions - 78.35.+c Brillouin and Rayleigh scattering; other light scattering 

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Copyright information

© EDP Sciences, Springer-Verlag, Società Italiana di Fisica 2000

Authors and Affiliations

  • R.J. Jiménez Riobóo
    • 1
  • K.-P. Bohn
    • 1
  • J.K. Krüger
    • 1
  1. 1.Fachrichtung Experimentalphysik 10.2, Universität des Saarlandes, Bau 38, Postfach 151150, 66041 Saarbrücken, GermanyDE

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