Structural phase transition in titanite, CaTiSiO5: A ramanspectroscopic study

✍ Scribed by Ekhard Salje; Claudia Schmidt; Ulrich Bismayer

• Book ID: 104662106
• Publisher: Springer-Verlag
• Year: 1993
• Tongue: English
• Weight: 463 KB
• Volume: 19
• Category: Article
• ISSN: 0342-1791
• DOI: 10.1007/bf00203191

✦ Synopsis

The structural phase transition in titanite is correlated with a strong temperature dependence of Raman scattering cross sections and, to a somewhat lesser extent, with shifts of the phonon frequencies. Their quantitative temperature evolution in the low-symmetry phase (P21/a) is compatible with a nearly 2D Ising behaviour with fl~ 0.12 and T~ = 497 K. At temperatures above 860 K, the phonon signals agree with A 2/a symmetry but not in the temperature interval between 497 K and 860 K. In this temperature range new structural states give rise to additional phonon signals. A model based on mobile APBs between slabs of P21/a material, first proposed by van Heurck et al. (1991), is in qualitative agreement with our experimental observations.