The β <-> α' phase transition of Sr2SiO4. II. X-ray and optical study, and ferroelasticity of the β form
Citations Over Time
Abstract
The transition between the monoclinic fl and orthorhombic a' phases of strontium orthosilicate was investigated by single-crystal diffractometry and polarizing microscopy at variable temperatures, on the basis of the disappearance or appearance of twin domains of the fl form. The phase change occurred sharply with thermal hysteresis in both experiments, at 364 and 355 K (X-rays) and at 369 and 359 K (light, best values out of a number of samples) for fl --, a' and a' --, fl, respectively; the optical study showed that transition temperatures are influenced by the size and habit of crystals. The orientations of fl and a' lattices are related by a simple rotation of the x axis. A first-order character is suggested by thermal results for the phase change, though it relates ordered and disordered structures. Crystals of fl-Sr2SiO 4 prove to be ferroelastic (Aizu's species mmmF2/m) with a spontaneous strain of 0.033. The mechanisms of the phase transition and of the transformation between mirrorrelated orientation states are discussed in relation to structural disorder of the paraelastic a' form.
Related Papers
- → An anomalous ferroelastic phase transition arising from an unusualcis-/anti-conformational reversal of polar organic cations(2023)13 cited
- → Optical studies of ferroelastic phase transition and domain structures in K3Na(SeO4)2 crystals(1996)71 cited
- → Lan dau-theoretical consideration of incommensurate phase transition in ferroelectrics and ferroelastic substances(1981)18 cited
- → Features of the Phase Transition in a Thin Ferroelastic Rod(2019)
- → Phase Transition Routes for ε- and γ-CL-20 Crystals under High Pressures of up to 60 GPa(2020)