Investigations on Bi25FeO40 powders synthesized by hydrothermal and combustion-like processes

What is it about?

Paper: https://www.researchgate.net/publication/262896133_Investigations_on_Bi25FeO40_Powders_Synthesized_by_Hydrothermal_and_Combustion-Like_Processes Abstract: The syntheses of phase-pure and stoichiometric iron sillenite (Bi25FeO40) powders by a hydrothermal (at ambient pressure) and a combustion-like process are described. Phase-pure samples were obtained in the hydrothermal reaction at 100 °C (1), whereas the combustion-like process leads to pure Bi25FeO40 after calcination at 750 °C for 2 h (2a). The activation energy of the crystallite growth process of hydrothermally synthesized Bi25FeO40 was calculated as 48(9) kJ mol-1. The peritectic point was determined as 797(1) °C. The optical band gaps of the samples are between 2.70(7) eV and 2.81(6) eV. Temperature and fielddepending magnetization measurements (5-300 K) show a paramagnetic behaviour with a Curie constant of 55.66x10-6 m3Kmol-1 for sample 1 and C=57.82x10-6 m3Kmol-1 for sample 2a resulting in magnetic moments of µmag=5.95(8) µB mol-1 and µmag=6.07(4) µB mol-1. The influence of amorphous iron-oxide as a result of non-stoichiometric Bi/Fe ratios in hydrothermal syntheses on the magnetic behaviour was additionally investigated.

Featured Image