Combustion synthesis of nanosized gamma-Fe2O3: Structural, electrical, dielectric and magnetic studies

Abstract

Combustion synthesis of nanosized ?-Fe2O3 using polyethylene glycol as a fuel has been reported. Four different precursors were taken to see the feasibility of conversion to ?-Fe2O3 in a single step. The as synthesised ?-Fe2O3 samples were characterised by X-ray diffraction (XRD), infrared (IR), transmission electron microscopy (TEM), electrical, dielectric, magnetic and Mössbauer techniques. The ?-Fe2O3 samples were found to crystallise in a cubic system. Unit cell parameters were obtained by least square refinement of the X-ray powder data using PROZSKI program. The crystallite sizes were calculated using X-ray line broadening. TEM studies showed that particles are in the range of 20-50 nm. X-ray, tap and apparent densities were determined and compared with the ?-Fe2O3 prepared by conventional methods. All the ?-Fe2O3 samples showed semiconducting behaviour. From dielectric studies it was observed that dielectric constant vary from 100 to 2000 depending upon the precursor used to prepare ?-Fe2O3 and number of Fe2+ and Fe3+ ions present in that sample. The saturation magnetisation of these samples are in the range of 40-50 emu/g.