Structural, cation distribution, mechanical, and optical properties of rare-earth doped cadmium zinc ferrites

The structural, mechanical, optical, and magnetic properties of RE³⁺ (Nd³⁺and Sm³⁺) doped cadmium zinc ferrites were investigated. The purpose of the rare-earth dopants is to deduce the possible applications for the prepared samples. The Cd_0.5Zn_0.5RE_xFe_2-xO₄ ferrite (x = 0.00, 0.01, 0.08) was synthesized using the wet chemical co-precipitation method. The structural investigations were done using X-ray diffraction (XRD) fitted using Rietveld refinement. The analysis confirmed the spinel structure's crystallinity belonging to the Fd3m space group. The cation distribution and many other structural parameters were estimated from the XRD data. Cation distribution calculations were done using a custom-built Python program that proved the normal structure of the prepared ferrites. The mechanical properties were calculated using the data extracted from Fourier transform infrared (FTIR) spectra, which showed an increase in porosity, weakening of elastic moduli, increase in ionic distances, and expansion of the unit cell. The optical properties were studied using Photoluminescence (PL) spectroscopy and Ultraviolet–Visible (UV–Vis) spectroscopy, which allowed the evaluation of the energy gaps that are found to range between 3.24 and 3.27 eV for the direct energy gap. The results confirmed the quantum confinement effect due to the decrease of crystallite size with the increase of the energy band gap. Optical analysis also showed that the prepared ferrites are good candidates for optoelectronics and nonlinear optical applications. Mössbauer spectroscopy and vibrating sample magnetometer (VSM) investigate the magnetic and structural properties that verified the superparamagnetic behavior in all samples.