Synthesis and magnetic characterization of iron-doped molybdenum trioxide (α-MoO 3 :xFe)

– We report a study on the properties of iron-doped molybdenum trioxide (MoO 3 :xFe) in different iron molar concentrations of 0% (pure), 1%, 3%, and 5%. The samples were prepared by solid-state reaction and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and Fourier transform infrared (FTIR) spectroscopy, electrical measurements, and vibrating sample magnetometry (VSM). Using XRD, the formation of pure orthorhombic molybdenum trioxide (α-MoO 3 ) has been detected for the pure sample, while for the MoO 3 :1%Fe, MoO 3 :3%Fe, and MoO 3 :5%Fe samples, monoclinic Fe 2 (MoO 4 ) 3 was formed as a secondary phase with subsequent Fe doping in the first α-MoO 3 phase. SEM images show the formation of MoO 3 plates and confirm the formation of the secondary phase, which crystallizes as cuboids. The percentages of Fe present in the MoO 3 and the secondary phase Fe 2 (MoO 4 ) 3 were measured by energy dispersive x-ray microanalysis (EDS). FTIR and Raman spectra have shown changes in structure with increasing percentages of Fe. Electrical measurements were made for all the samples to determine how the dopant changes the material's current-voltage curves ( I×V ) and conductivity (σ). Results show a decrease of σ with the increase of Fe as a dopant. The magnetic characterization at room temperature revealed an increase in magnetization from the pure α-MoO 3 to the MoO 3 :1%Fe, followed by a decrease in MoO 3 :3%Fe, and then a substantial increase for MoO 3 :5%Fe. For magnetic field ranges close to 2900 Oe.