X-Ray diffraction on large single crystals using a powder diffractometer

Abstract

Information on the lattice parameter of single crystals with known crystallographic structure allows for estimations of sample quality and composition. In many cases, it is sufficient to determine one lattice parameter or the lattice spacing along a certain, high-symmetry direction, e.g. in order to determine the composition in a substitution series by taking advantage of Vegard’s rule. Here we present a guide to accurate measurements of single crystals with dimensions ranging from 200 m up to several millimetres using a standard powder diffractometer in Bragg–Brentano geometry. The correction of the error introduced by the sample height and the optimisation of the alignment are discussed in detail. In particular for single crystals with a plate-like habit, the described procedure allows for measurement of the lattice spacings normal to the plates with high accuracy on a timescale of minutes.

Keywords:

• X-Ray diffraction
• single crystal
• lattice parameter determination
• powder diffractometer

Acknowledgements

The authors thank F. Freund, Th. Grünwald, H. Hodovanets, J. Maiwald, S. Ran and V. Taufour for fruitful discussions.

Notes

No potential conflict of interest was reported by the authors.

Former address: The Ames Laboratory, Iowa State University, Ames, IA, USA.

Additional information

Funding

This work was supported by the Deutsche Forschungsgemeinschaft through the Emmy-Noether program [grant number JE 748/1-1]; the U.S. Department of Energy, Office of Basic Energy Science, Division of Materials Sciences and Engineering; the research was performed at the Ames Laboratory. Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University [contract number DE-AC02-07CH11358].