ISSN:
1600-5740
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Rietveld analysis of neutron powder diffraction data on the sanmartinite (ZnWO4)-cuproscheelite (CuWO4) solid solution has enabled the comparison of microscopic and macroscopic order parameters associated with the P2/c–P\overline 1 structural phase transition. The macroscopic spontaneous strain, calculated from the lattice parameters, conforms well with a second-order Landau model. Furthermore, this is also true of the symmetry-related atomistic M—O order parameter and the quadratic elongation of the MO6 octahedra. It is clear that the Jahn–Teller effect, associated with the divalent Cu cation, is the driving force for the phase transition and the excess elongation evident in the M—O(2) bond giving rise to the non-symmetry predicted strain element e22. The existence of a large region of order parameter saturation at the copper-rich end of the solid solution is also associated with the MO6 elongation and the breakdown of the homogeneous strain field of the zinc solute atoms.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0108768196010403
