Impact of cation distribution on structural, morphological, optical and low-temperature magnetic properties of Er3+ substituted Cu0.8Cd0.2Fe2O4 nanoparticles

Abstract

A series of cubic spinel-shaped Cu-Cd ferrites using Er3+ ion doping, Cu0.8Cd0.2ErxFe2-xO4 (x = 000, 0.0010, 0.0015, 0.0020, 0.0025, and 0.0030-CCEF) had been synthesized using the citrate sol-gel auto combustion approach. The structural, optical and magnetic properties of the samples were investigated using a wide range of characterization techniques, such as Thermogravimetric and Differential thermal analysis (TG-DTA), Powder x-ray diffractometer (P-XRD), High-resolution transmission electron microscopy (HR-TEM), UV–VIS, Electron spin resonance (ESR), and Vibrating sample magnetometer (VSM). To obtain an understanding of the existence of hydrated water and comprehend the degradation behavior, the TG-DTA was carried out. The produced powders were then sintered for 240 min at 500 °C. According to X-ray diffraction spectra, the John-Teller ion (Cu2+) causes a tetrahedral deformation for pure Cu-Cd ferrite. Erbium substituted afterwards transformed the tetragonal phase towards the cubic spinel phase including trace amounts of impurity phase. FESEM and HRTEM analysis were employed to investigate the microstructure. These FESEM and HRTEM images' observations demonstrated that nanoparticles have a spherical shape. Furthermore, the findings showed that the as-prepared spinel Cu-Cd ferrite nanoparticles exhibited a determined optical band gap energy in the region of 1.62–1.91 eV, demonstrating the semiconducting properties of the synthesized materials. In order to calculate the spin resonance parameters such as the g-values, peak-to-peak linewidth and resonance field, ESR spectra accumulated with X-band microwave energy have been fitted using the Lorentzian function. At 15 K, an in-depth examination of the ferrite nanoparticles' magnetic characteristics was performed. The prepared sample has shown indications of developing superparamagnetic behavior.