Structural, optical and magnetic properties of Tb3+ substituted Co nanoferrites prepared via sonochemical approach.

This paper emphasizes the structure, morphology, optical, and magnetic properties of sonochemically prepared terbium-substituted cobalt ferrite nanoparticles, CoTb x Fe 2-x O 4 (0.00 ≤ x ≤ 0.10). The formation of cubic spinel nanosized ferrite structure was confirmed by X-ray diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), and Fourier-transform infrared (FT-IR) spectroscopy. The crystallites sizes were found in the range of 11–14 nm. Ultraviolet–visible percentage diffuse reflectance investigations were performed on pristine and Tb3+-doped cobalt spinel ferrite CoFe 2 O 4 nanoparticles. The direct energy band gap (E g) values were determined by applying the Kubelka–Munk theory and Tauc plots were found to be in a narrow band range of 1.37–1.44 eV. Analyses of magnetization versus the magnetic field (M(H)) were performed. The magnetic parameters, including the saturation magnetization (M s), squareness ratio (SQR = M r /M s), magnetic moment ( n B ), remanence (M r), and coercivity (H c) were evaluated. The M(H) curves exhibited a soft ferrimagnetic nature. It was demonstrated that the Tb3+ substitutions strongly influenced the magnetization data. Indeed, the M s , M r , H c , and n B values decreased with increasing Tb3+ substitution. [ABSTRACT FROM AUTHOR]