Structural phase transitions and conduction properties of superionic, ferroelastic Cu₆PS₅Br_1−xI_xsingle crystals (x= 1, 0.75, 0.5, 0.25)

Abstract

The structural origin of Cu + ions conductivity in Cu 6 PS 5 I single crystals is described in terms of structural phase transitions studied by X-ray diffraction, polarizing microscope and Influence of the copper stechiometry on the T c is also discussed.

Diffusion paths formation for Cu+ ions in superionic Cu6PS5I single crystals studied in terms of structural phase transition

“…Recently, we reported a structural PT diagram for this compound based on X-ray diffraction, domain structure observations and calorimetric measurements [18]. The observations under a polarizing microscope did not evidence any domain structure in our samples above T c ¼ ð1442169Þ K. Below T c , the crystal belongs to ferroelastic phase with monoclinic symmetry Cc.…”

“…This has an influence on the temperature of superionic PT, which varies in the range of 144-169 K for different samples. However, in our previous work [18], we showed that in Cu 6 PS 5 I crystals temperature of the superionic PT is at the same time the temperature of ferroelastic PT T c . Moreover, the temperature of this transition also depends on copper content in the sample.…”

Hexacopper(I) phosphorus(V) bromide penta(selenide/sulfide), Cu6P(Se0.7S0.3)5Br

“…Copper-and silverbased argyrodites are efficient ionic conductors. However, the ionic conductivity shows a significant dependence on the composition (Beeken et al, 2003(Beeken et al, , 2005Gagor et al, 2006).…”