Thickness of pericline twin walls in anorthoclase: an X-ray diffraction study
Hayward, Stuart A.; Chrosch, Jutta; Salje, Ekhard K. H.; Carpenter, Michael A.
European Journal of Mineralogy Volume 8 Number 6 (1997), p. 1301 - 1310
published: Jan 8, 1997
manuscript accepted: Jul 16, 1996
manuscript received: Apr 15, 1996
ArtNo. ESP147050806009, Price: 29.00 €
Abstract The thickness of pericline twin walls in disordered feldspar Ab65Or30An5 has been determined by quantitative measurements of the diffuse X-ray diffraction caused by these walls. The diffuse diffraction appears as streaking between pairs of twin-related Bragg peaks. Comparison of the predictions of simple model calculations with the observed intensity profiles indicates that these walls are ≈ 25 Å thick at room temperature. On heating, the wall thickness increases, following the predictions of Ginzburg-Landau theory: W ∞ |Tc-T-1/2.