Mössbauer studies on thermal decomposition of rubidium bis(citrato)ferrate(III) precursor prepared by precursor method

• The methods used result in formation of particles with average size of 30 and 65 nm.
• Mossbauer studies show super-paramagnetic phase in the final ferrite product.
• XRD pattern confirms the formation of cubic ferrite with α-LiFeO2 type geometry.

Thermal decomposition studies of rubidium bis(citrato)ferrate(III) trihydrate precursor has been carried out in flowing air atmosphere from ambient temperature to 900 °C. The precursor material was prepared by using solution based precursor method and different physico-chemical techniques i.e. simultaneous thermogravimetry – differential thermogravimetry – differential thermal analysis (TG–DTG–DTA), X-ray diffraction (powder), transmission electron microscopy (TEM), infra-red (IR) and Mössbauer spectroscopy have been employed to characterize the intermediates and end product. After dehydration, anhydrous precursor undergoes exothermic decomposition to yield various intermediates like metal carbonate, metal oxide and α-Fe2O3, followed by a solid-state reaction to form final ferrite product above 800 °C. XRD study reveals the formation of pure and nanosized rubidium ferrites with α-LiFeO2 type geometry. TEM micrograph confirms the nanosized particles with average size of 65 nm. For the sake of comparison, similar ferrite has also been prepared by the combustion method at a comparatively lower temperature (600 °C) and in less time.