A high-resolution synchrotron powder diffraction study of substituted gallium ferrites using flat-plate fixed angle of incidence geometry on beamline I11 at Diamond

作者：Ryding S H M; Azough F; Freer R; Cernik R J^*; Tang C C; Thompson S P

来源：Journal of Applied Crystallography, 2012, 45: 174-181.

DOI：10.1107/S0021889812001690

Very high resolution powder diffraction structural studies of the potentially room temperature multiferroic Ga2-xFexO3 solid solution series (x = 0.7-1.3, 0.1 steps) have been undertaken using a fixed angle of incidence geometry. The applied absorption correction was seen to improve the goodness of fit (chi(2)) of the Rietveld refinements from an average of 1.41 to 1.06. The correction also resulted in an increased mean isotropic displacement parameter from 0.5 to 0.65. The mean difference in the fractional coordinates of the atoms between the refined models from the corrected and uncorrected data was 0.0007 angstrom, compared with the mean fractional coordinate error of 0.0003 angstrom. It is concluded that the final crystal structures refined from the corrected and uncorrected data are not significantly different. The number of reflections in each data set was over 2700, and the average peak half-width was 0.018 degrees with the data binned in 4 millidegree steps. The data quality allowed bond length and angle determinations of sufficiently high accuracy to measure significant metal site distortions to an average precision of +/- 0.007 angstrom. A lattice parameter nonlinearity was observed on either side of the x = 1 composition; this was attributed to local distortions, primarily of the Fe1 and Ga2 sites.

• 出版日期2012-4