Magnetic and structural properties of single-phase Gd3+-substituted Co–Mg ferrite nanoparticles

Abstract

Nanocrystalline Gd³⁺-doped Co–Mg ferrite nanoparticles with the chemical formula Co_0.7Mg_0.3Fe_(2−x)Gd_xO₄ (x = 0.02) were prepared by coprecipitation for the first time. The properties of the nanoparticles were investigated by X-ray diffraction, confirming a single-phase, highly crystalline cubic spinel structure in the space group Fdm and an average crystallite size of 54 nm. The Fourier-transform infrared spectrum showed two fundamental absorption bands in the wavenumber range of 437–748 cm⁻¹ attributed to the stretching vibration of tetrahedral and octahedral sites in the spinel structure. Scanning electron microscopy analysis showed that the nanoparticles are different in shape and slightly agglomerated. Energy-dispersive X-ray spectroscopy demonstrated the purity of the nano-ferrite powder. Magnetic measurements revealed ferrimagnetic behavior at room and low temperatures with high coercivity and a high saturation magnetization of 95.68 emu g⁻¹, larger than that of pure bulk cobalt ferrite (80.8 emu g⁻¹). Only ferrite cobalt synthesized sonochemically has been reported to have a higher saturation magnetization (92.5 emu g⁻¹).