Study of the crystal and electronic structures of (Bi1-xNdx)FeO3 compositions using Rietveld refinements and the maximum entropy method

摘要

In this work we present a methodology that combines the Rietveld structure refinement and the Maximum Entropy Method (MEM) to analyze the crystal and electronic structures, and the chemical bonding of the Bi1-xNdxFeO3 compositions for x = 0.025, 0.05, 0.075, 0.10, 0.15 and 0.20. A structural phase modification from rhombohedral R3c to orthorhombic (Pnma) was observed with the increase in the neodymium content. As an intermediate phase in the transition from R3c to Pnma, a monoclinic structure (C2/m) took place. Electron density calculations provided the observation of a total suppression of the covalent bonds between the bismuth and oxygen ions for x = 0.10 and the emergence of the covalent character between all the bonds for x = 0.20.