Estudo do Bi nanoestruturado em condições de alta pressão

Abstract

A mixture of Bi67Zn33 was subjected to 5 hours of mechanical milling for homogenization and nanometrization. The mixture was investigated by the angledispersive X-ray diffraction method under non-environmental conditions in the Brazilian Synchrotron Light Laboratory using a diamond anvil cell with a membrane. The mixture demonstrated four phase transtions of the Bi structure under pressure of 44 GPa. Moreover, one of the above phase exhibited an incommensurale structure. All the diffractograms were refined using the Rietveld method. However, the immeasurable structure was studied using the pseudo-two-phase method. The refinement procedure yielded the variation of unit cell, deformation map, and the average size crystallite as a pressure function. The compressibility was obtained using the Birch-Murnaghan equation of state the. Density-functional theory was utilized to calculate the behavior of Bi under pressure. A detailed comparison was performed between the experimental measurements and the theoretical calculations.