Structural study of bismuth ferriteBiFeO3by neutron total scattering and the reverse Monte Carlo method

Abstract

We report a study of the atomic structure of the multiferroic material bismuth ferrite BiFeO 3 using neutron total scattering measurements coupled with analysis using the Reverse Monte Carlo method. We have examined average neighboring interatomic distances and local coordination environments, together with their fluctuations, for temperatures between 16 and 800 K (the sample decomposed at higher temperatures). There is little change in the average structure as a function of temperature, but the results show unusually large thermal motion at higher temperatures. No anomalous behavior is seen within this range, suggesting that the anomalies reported to occur below room temperature most likely arise due to effects associated with surfaces and interfaces.

Quantitative understanding of negative thermal expansion in scandium trifluoride from neutron total scattering measurements

“…Instead, at high temperature ScF 3 behaves as a typical harmonic crystal, or at least as one whose behavior is only weakly perturbed by anharmonic effects. A similar conclusion was obtained from an RMC study of BiFeO 3 based on neutron total scattering data; in spite of very large atomic motions at high temperature, the average structure remains robustly constant across a wide range of temperatures and there are no unusual changes in atom distributions [74].…”

Neutron powder-diffraction study of phase transitions in strontium-doped bismuth ferrite: 1. Variation with chemical composition

“…Using neutron powder diffraction, we study the variation of atomic and magnetic structures with both composition and temperature. We focus on samples with values of x in the range 0.1-0.16, and compare these data with our previous results for a sample with x = 0 [7]. In a second paper (in preparation) we will report further measurements obtained in a separate study that will focus more on the variation with temperature at higher concentrations.…”

“…The nuclear structure of BiFeO 3 at ambient temperature-denoted as the α phase-is that of a classical distorted perovskite structure [1,2,7,20], with polar rhombohedral space group R3c, as seen in other oxides such as sodium niobate at low temperature [21]. The crystal structure of α-BiFeO 3 is shown in figure 1.…”

“…Many of the key features of BiFeO 3 have been reviewed by Catalan and Scott [3] and Park et al [4]. BiFeO 3 has a typical perovskite structure with octahedral rotation and ferroelectric distortions from a parent high-symmetry cubic structure [5], giving a crystal structure of rhombohedral symmetry [1,2,6,7].…”

Orientational order/disorder and network flexibility in deuterated methylammonium lead iodide perovskite by neutron total scattering

“…The congurations can therefore give information about the distributions of orientations of molecules and molecular ions in ordered, partially ordered and disordered phases, [15][16][17][18][19][20][21] and about uctuations within inorganic crystal networks. 6,22,23 We believe that the total scattering method coupled with RMC analysis gives a unique view of disordered crystalline materials. 12,14 In the next section we give the crystallographic background necessary to understand the scientic problem being tackled in this paper.…”