https://doi.org/10.1007/s100510050081
Elastic anomalies and orientational glass transition in Na(CN)xCl1-x mixed crystals. A Brillouin spectroscopic study
Fachrichtung Experimentalphysik 10.2, Universität des Saarlandes, Bau 38,
Postfach 151150, 66041 Saarbrücken, Germany
Received:
8
April
1999
Revised:
3
June
1999
Published online: 15 February 2000
High performance Brillouin spectroscopy (BS) has been used to study the elastic
properties (static and dynamic) of the orientational glassy state of
Na(CN)xCl 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
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
-minimum. The temperature behaviour of the
longitudinal elastic constant c11 of very dilute
Na(CN)xCl
samples shows two striking features: i) Similar to the anomalous
temperature behaviour of
, lowering the temperature
first
decreases, goes through a minimum and then rises again. The minimum takes place at a
temperature above the temperature,
, where
reaches its minimum
value. ii) A kink-like anomaly of
is observed at lower temperatures. This
second anomaly is similar to the classical one observed in canonical glasses at their
glass transition temperature Tg.
PACS: 62.20.Dc – Elasticity, elastic constants / 64.70.Pf – Glass transitions / 78.35.+c – Brillouin and Rayleigh scattering; other light scattering
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000