exploring bismuth-induced structural modifications and magnetic phase transitions in cufe2o4 ferrite

The effects of diamagnetic bismuth substitution on the microstructural and magnetic properties of sol-gel auto-combustion citrate nitrate synthesized cufe2-xbixo4 (x=0.0, 0.4, 0.8, 1.2, 1.6 and 2.0) nano powders were investigated. the samples were characterized by techniques such as x-ray diffraction, raman spectroscopy, fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, energy-dispersive x-ray spectroscopy, uv-vis diffuse reflectance spectroscopy, and vibration sample magnetometer. the structural results showed a phase transition from a predominantly tetragonal structure with an i41/amd space group to a tetragonal structure with a p ncc space group. the magnetic properties of the samples revealed a transition from a ferrimagnetic to a diamagnetic phase due to the presence of the diamagnetic bi3+. although the coercive field exhibited a minimum value at a substitution level of x = 0.8, the saturation magnetization was found to decrease with increasing bi substitution, ranging from 25.04 emu/g for x = 0.0 to -0.02 emu/g for x = 2.0.