Comparison of structural, optical, electrical and magnetic properties between Ni0.5Co0.5Gd0.005Tb0.005Fe1.99O4 and Ni0.5Co0.5Gd0.0033Tb0.0033Dy0.0033Fe1.99O4

In this work, rare-earth (RE) ions, specifically Gd, Tb, and Dy, were simultaneously doped into a nickel cobalt ferrite (Ni0.5Co0.5Fe2O4) matrix to compare the enhancement of its electrical, magnetic, and optical properties depending on the number of distinct RE-ions in the matrix. Two compositions having distinct number of RE-ions that is NCR1 (Gd0.005 and Tb0.005) and NCR2 (Gd0.0033, Tb0.0033, and Dy0.0033) at Fe-site of the matrix, were prepared using the sol-gel technique. Both compositions exhibited the spinel phase according to the studies X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. Microstructure observed from micrographs revealed that NCR2 had a relatively porous structure and larger grain size compared to NCR1. This suggests that the different doping compositions can influence the microstructure of the material, which can impact its properties. An increase in the Curie temperature (the temperature at which a material loses its ferromagnetic properties) was noted for NCR2, indicating improved magnetic behavior. An improvement in magnetostriction behavior for NCR2 implies that it can be used in applications where precise control of shape or mechanical properties in a magnetic field is required. The enhanced properties in NCR2 were attributed to the multicity of impurity doping (Gd, Tb, Dy), which led to structural changes within the material.