A detail investigation on the structural, elastic, magnetic and dielectric properties of rare earth Dy3+ substituted Fe rich cobalt ferrite nanoparticles

This work is a comprehensive study on the structural, magnetic and dielectric properties of dysprosium-substituted cobalt ferrite (CFO) spinels Co 0·9 Fe 2.1-x Dy x O 4 (x = 0.0, 0.025, 0.05, 0.075, and 0.1). The series was synthesized via the sol-gel autoignition method, followed by rigorous characterization to elucidate the effects of Dy substitution on the material properties. X-ray diffraction (XRD) analysis confirmed the formation of a single-phase cubic spinel structure with a slight increase in cell parameter due to the substitution of Dy 3+ ions for smaller ionic radius Fe 3+ ions. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed uniform particle distribution, with a gradual increase in particle size corresponding to higher Dy concentrations. Fourier-transform infrared spectroscopy (FTIR) confirmed the preservation of the characteristic spinel framework. Elastic property measurements showed a reduction in Young's modulus, rigidity modulus, and bulk modulus with increasing Dy content, indicating material softening. Magnetic studies demonstrated an increase in saturation and remanent magnetization with Dy substitution, while coercivity and magnetic anisotropy exhibited non-linear trends. The dielectric analysis revealed a frequency-dependent decrease in the dielectric constant and higher dielectric losses at lower frequencies, both of which were influenced by Dy incorporation. These results highlight the tunable nature of magnetic and dielectric properties in Dy-substituted cobalt ferrites, making them promising candidates for high-frequency inductors, electromagnetic interference (EMI) shielding, and data storage applications. • Dysprosium (Dy) substitution in Co 0·9 Fe 2.1-x Dy x O 4 spinel ferrites increases the lattice constant due to the larger ionic radius of Dy 3+ , confirmed by XRD and cation distribution analysis. F0B7 • Magnetic measurements revealed enhanced saturation magnetization (Ms) and remanent magnetization (Mr) with Dy substitution, attributed to cation redistribution and the high magnetic moment of Dy 3+ ions. F0B7 • Elastic properties, including Young's modulus, rigidity modulus, and bulk modulus, decreased with increasing Dy content, indicating material softening due to lattice expansion and weakened bond strength. F0B7 • Dielectric constant decreased with frequency and Dy content, while dielectric losses (tanδ) increased, reflecting disrupted polarization and increased charge carrier scattering. F0B7 • The tunable magnetic and dielectric properties of Dy-substituted cobalt ferrites make them promising candidates for high-frequency inductors, electromagnetic interference (EMI) shielding, and data storage devices.