High pressure x-ray diffraction studies of the nanostructured Ge34Sb66 solid solution produced by mechanical alloying

Abstract

A nanostructured solid solution of Ge34Sb66 produced by mechanical alloying was investigated by the angle-dispersive X-ray diffraction method from synchrotron radiation by using a diamond anvil cell technique. Pressure induced phase transitions were observed. Starting from A7 symmetry at ambient conditions, Ge34Sb66 was transformed to a high pressure host-guest structure at 12.0 GPa. The compressibility and bond distances of A7 phase were determined by the Rietveld refinement of the x-ray diffraction data. The lattice parameters and cell volume were described by Birch–Murnaghan equation-of-state. The Bragg peaks of the A7 structure show a strong reflection-indices-dependent line-broadening due to the applied pressure. Hence, they were simulated by Stephens's model. The host-guest X-ray pattern was simulated by the Pseudo-two-phase Rietveld method.