Revised crystal structure and electronic properties of high dielectric Ba(Fe1/2Nb1/2)O3 ceramics

Ba(Fe1/2Nb1/2)O-3 ceramics are considered to be promising for technological applications owing to their high dielectric constant over a wide range of temperatures. However, there exists considerable discrepancy over the structural details. We address this discrepancy through a combined x-ray diffraction at room temperature and neutron powder diffraction measurements in the range from 5 K up to room temperature, supplemented by a comparative analysis of the earlier reported structures. Our study reveals a cubic structure with space group P m 3 over bar m at all measured temperatures. Further, the x-ray near edge structure and extended x-ray absorption fine structure studies on the local environment of the Fe ions is consistent with the cubic symmetry. An appropriate value of U for DFT+ U calculations is obtained by comparison with x-ray absorption spectroscopy, which agrees well with the earlier reported electronic properties.

Automated summary

The study resolved the discrepancies over the structural details of Ba(Fe1/2Nb1/2)O-3 ceramics through X-ray diffraction and neutron powder diffraction measurements, revealing a cubic structure. An appropriate value of U for DFT+U calculations was obtained through comparison with X-ray absorption spectroscopy.