The Bi2O3–Fe2O3–Sb2O5 system phase diagram refinement, Bi3FeSb2O11 structure peculiarities and magnetic properties

• The Bi2O3–Fe2O3–Sb2O5 system phase diagram refinement has been performed.
• The Bi3FeSb2O11 existence along with pyrochlore structure compound is shown.
• It was determined that the Bi3FeSb2O11 is of disordered cubic KSbO3-type structure.
• Factor group analysis of Bi3FeSb2O11 vibrational spectrum has been performed.
• Short-range antiferromagnetic interactions govern Bi3FeSb2O11 magnetic behavior.

The refinement of the Bi2O3–Fe2O3–Sb2O5 system phase diagram has been performed and the existence of the two ternary compounds has been confirmed. The first one with a pyrochlore-type structure (sp. gr. Fd 3̄m) exists in the wide solid solution region, (Bi2−xFex)Fe1+ySb1−yO7±δ, where x=0.1–0.4 and y=−0.13–0.11. The second one, Bi3FeSb2O11, corresponds to the cubic KSbO3-type structure (sp. gr. Pn 3̄) with unit cell parameter a=9.51521(2) Å. The Rietveld structure refinement showed that this compound is characterized by disordered structure. The Bi3FeSb2O11 factor group analysis has been carried out and a Raman spectrum has been investigated. According to magnetization measurements performed at the temperature range 2–300 K it may be concluded that the Bi3FeSb2O11 magnetic properties can be substantially described as a superposition of strong short-range antiferromagnetic exchange interactions realizing inside the [(FeSb2)O9] 3D-framework via different pathways.

The refinement of the Bi2O3–Fe2O3–Sb2O5 system phase diagram has been performed and the existence of the solid solution with a pyrochlore-type structure (sp. gr. Fd 3̄m) and Bi3FeSb2O11, correspond of the cubic KSbO3-type structure (sp. gr. Pn 3̄) has been confirmed. The structure refinement, Raman spectroscopy as well as magnetic measurements data of Bi3FeSb2O11 are presented.Figure optionsDownload as PowerPoint slide