Negative thermal expansion in crystals with the delafossite structure: An extended x-ray absorption fine structure study of CuScO2 and CuLaO2

Content Provider	Semantic Scholar
Author	Ahmed, Syed Iliyas Dalba, Giusepe Fornasini, P. Vaccari, Mattia Sanson, Anne
Copyright Year	2009
Abstract	Extended x-ray absorption fine structure has been measured at the K edge of copper in CuScO2 and CuLaO2 to investigate the local origin of negative thermal expansion NTE along the c axis. A positive expansion of the Cu-O bond has been measured within the entire temperature interval to be contrasted with the negative expansion of the distance between average atomic positions measured by diffraction; the inadequacy of the riding correction to diffraction data has been evidenced. The weak temperature dependence of the parallel mean-square relative displacement MSRD indicates a rather stiff Cu-O bond, while the large perpendicular MSRD measures an intense relative motion of copper with respect to oxygen atoms perpendicular to the c axis. The comparison between the two compounds enlightens the relevance of the correlation of perpendicular motion to quantitatively explain the apparent NTE of the Cu-O bond.
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Alternate Webpage(s)	http://alpha.science.unitn.it/~rx/raggi_x/rx_pdf_articoli/96_09_PRB_delaf.pdf
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article