Role of rare earth doping on structural, elastic, optical, and magnetic properties of Co-Cu spinel ferrite nanoparticles prepared by sol gel auto-combustion (SGAC) route

Abstract

This study provides a comprehensive investigation of structural, elastic, optical, and magnetic characteristics of various rare earth elements substituted Co-Cu ferrite nanoparticles Co_0.5Cu_0.5RE_0.05Fe_1.95O₄ (CCRE) (RE: Y³⁺, Dy³⁺, and Pr³⁺) synthesized by the sol-gel auto-combustion (SGAC) route. XRD revealed a nanocrystalline spinel phase with an average crystallite size 35 nm after Rietveld refinement. The cation distribution showed that RE³⁺ ions preferred to occupy the octahedral site. Using FTIR data, the force constant for the tetrahedral and octahedral sites was determined to obtain stiffness constants; while the elastic moduli (Young's modulus, bulk modulus, and rigidity), Poisson's ratio, and Debye temperature were computed based on the stiffness constants. The optical band gap increased when Co-Cu spinel ferrite doped with Y³⁺ and Pr³⁺ while decreased with Dy³⁺, and the refractive index reciprocated. Furthermore, interesting magnetic parameters as saturation magnetization, coercivity, anisotropy constant and Yafet–Kittel angles were obtained for the investigated samples. The microwave frequency (W_m) values for all CCRE nanoparticles fall within the range of 4.75 GHz–9.82 GHz. The low field approximation of Langevin equation was used to discuss the correlation between the magnetic properties of investigated nanoparticles and the switching field distributions (SFD) of CCRE nanoferrites. Ultimately, the magneto-mechanical and magneto-optical characteristics of Co-Cu nanoferrite doped with RE³⁺ provide opportunities for numerous applications.