Structural, Optical, Dielectric and Magnetic properties of Nd 3+ doped Co-Zn Nanoferrites Synthesized by Citrate Gel Auto-combustion method

Rare earth Neodymium-doped cobalt-zinc nanoferrite with compositions of Co _0.2 Zn _0.8 Nd _x Fe _2−x O ₄ (where x  = 0.00 to 0.025 with the step of 0.005) synthesised by citrate gel auto-combustion process. The investigation has been done into the nanoparticle’s crystal structure, morphology, particle size, optical, dielectric, and magnetic characteristics.The study of the X-ray diffractometer (XRD) revealed the development of a cubic spinel structure. The computed crystallite size of the samples ranges from 33.467 nm to 36.465 nm, with Nd³⁺ doping increasing. The cation distribution evaluated from XRD data suggests that Zn²⁺ and Fe³⁺ ions occupy the tetrahedral (A)-site, whereas Fe³⁺, Nd³⁺, and Co²⁺ ions occupy the octahedral (B)-site. The shape of the ferrites was investigated by using Field Emission Scanning Electron Microscope(FESEM) images. The FESEM pictures show nanocrystalline particles organised in layers with a porous structure. The High-Resolution Transmission Electron Microscopy (HRTEM) image revealed particles of spherical shape with a mean diameter of 62 nm. The lattice fringe width in HRTEM verifies the emergence of pure spinel phase in the Nd³⁺ doped Co-Zn ferrite. The Selected Area Electron Diffraction (SAED) picture of the ferrite was used to confirm the peaks exhibited by the XRD data. The FTIR data reveals the formation of the spinel ferrite by showing two characteristic absorption peaks at 400–424 cm⁻¹ and 5588 − 572 cm⁻¹. Tauc plots were stripped of direct band gaps (Eg), and the values were discovered in a tiny energy range between 3.010 and 3.297 eV. The dielectric investigation is carried out utilising complex impedance spectroscopy at frequencies ranging from 1 Hz to 6 MHz. The dielectric properties, such as real (ε'), and imaginary (ε'') parts, in addition to loss tangent (tan δ), decreased utilising rising frequency for prepared ferric materials. The dielectric results were confirmed, and AC conductivity increased with frequency, implying that the conduction mechanism is due to tiny polaron hopping between cations. The study of complex impedance results revealed "the capacitive and reactive features." The electrical characteristics of produced nano ferrites are considerably influenced by replacing Fe ions with Nd³⁺ ions. The Vibration Sample Magnetometer (VSM) obtained the magnetic characteristic hysteresis loops of synthesised samples at room temperature. The results showed that all Nd³⁺-doped samples exhibited a ferromagnetic nature. At the temperature, the maximum saturation magnetisation was observed for X = 0.000-0.025. The values were found in the range of 12.011. The observed SQR values revealed the single-domain structure of prepared samples.