Structural, morphological and magnetic properties of (Ni0.5Co0.5)[Ga Gd Fe2–2]O4 nanoparticles prepared via sonochemical approach

Abstract

In this report, the impact of Ga3+ and Gd3+ co-substitution on different types of behavior of Ni-Co nanospinel ferrites (NSFs), (Ni0.5Co0.5)[GaxGdxFe2–2x]O4 (0.000 ≤ x ≤ 0.025), was investigated. NSFs were fabricated through ultrasound irradiation. The structure, composition, and spherical morphology of all products were verified by numerous characterization techniques such as X-ray diffraction (XRD), scanning and transmission electron microscopes (SEM & TEM), and selected area electron diffraction (SAED). Mossbauer spectra are composed of two ferromagnetic sextets and one paramagnetic doublet. These spectra were fitted to extract hyperfine parameters of the doped samples. Both sublattices' hyperfine magnetic field decreases with substitution. The isomer shift values show that the Mossbauer spectra are composed of magnetic Fe3+ sextets. The magnetization measurements at variable magnetic field (M-H) were investigated via a vibrating sample magnetometer (VSM) at a variable magnetic field (M-H) at temperatures (T) from 300 and 10 K. All NSFs disclose ferrimagnetic behavior at both 300 and 10 K where they are soft and hard, respectively. We determine that the remanence magnetization (Mr), saturation magnetization (Ms), and magneton number (nB) decrease with increasing Ga3+ and Gd3+ ions contents. The reduction in these values was predominantly recognized to the impact of cation redistribution and surface spins on tetrahedral (Td) and octahedral (Oh) sites. As the Ga3+ and Gd3+ contents increase, the coercivity (Hc) is also found to decrease.