The crystalline structures of superionic high temperature copper selenides Cu2−xSe (0≤x≤0.25) produced by Mechanical Alloying were investigated using X-ray diffraction (XRD) technique. The measured XRD patterns showed the presence of the peaks corresponding to the crystalline superionic high temperature α-Cu2Se phase in the as-milled sample, and its structural data were determined by means of a Rietveld refinement procedure. After a heat treatment in argon at 200∘C for 90 h, this phase transforms to the superionic high temperature α-Cu1.8Se phase, whose structural data where also determined through the Rietveld refinement. In this phase, a very low occupation of the trigonal 32(f) sites (∼3%) by Cu ions is found. In order to explain the evolution of the phases in the samples, two possible mechanisms are suggested: the high mobility of Cu ions in superionic phases and the intense diffusive processes in the interfacial component of samples produced by Mechanical Alloying.
@article{arxiv.cond-mat/0402012,
title = {Structural study of Cu$_{2-x}$Se alloys produced by mechanical alloying},
author = {K. D. Machado and J. C. de Lima and T. A. Grandi and A. A. M. Gasperini and C. E. Maurmann and S. M. Souza and C. E. M. Campos and A. F. Pimenta},
journal= {arXiv preprint arXiv:cond-mat/0402012},
year = {2009}
}