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Item A study on solubility of bismuth cations in nickel cobalt ferrite nanoparticles and their influence on dielectric and magnetic properties(Elsevier Ltd, 2023) Patil, S.; Meti, S.; Kanavi, P.S.; Bhajantri, R.F.; Anandalli, M.; Mondal, R.; Karmakar, S.; Muhiuddin, M.; Rahman, M.R.; Kumar, B.C.; Hegde, B.G.In this work, a low temperature (∼600 °C) solution combustion technique is employed for the synthesis of Ni0.5Co0.5BixFe2-xO4 (NCBFO, where x = 0.0, 0.05, 0.1, 0.15, & 0.2) nanoparticles with crystallite size variation of 17–22 nm. The X-ray diffraction (XRD) technique is used to confirm the formation of cubic spinel phase of Bi3+ doped (for x ≤ 0.05 samples) nickel–cobalt ferrite (NCFO) nanoparticles. The increase in bismuth substitution (x > 0.05) results in the formation of the Bi2O3 along with the NCFO structure, which results in the reduction of binding energy and is confirmed by the XRD and X-ray photoelectron spectroscopy (XPS) techniques. From the Raman spectra, the change in the intensities of the peaks is observed due to the variation of Bi3+ in NCFO matrix. Due to increasing cation concentration and electronegativity, the FTIR absorption band shifts toward the lower wave numbers. Dielectric measurements were carried out to examine the charge transport behavior and electric conduction mechanism. The FESEM images shows the non-magnetic bismuth atoms are diffused into the NCFO nanoparticles. From the vibrating sample magnetometer (VSM) analysis, it is observed that saturation magnetization, remanent magnetization, coercivity and squareness ratio are found to be maximum for x = 0.15 NCBFO sample. The high coercivity (Hc = 916.8 Oe) for the x = 0.15 sample indicates the hard ferromagnetic behaviour of the samples. © 2023 Elsevier B.V.Item Investigation of structural, thermal, magnetic, and dielectric properties of Yb+3 doped nickel cobalt ferrite nanomaterial for electro-magnetic applications(Springer, 2024) Patil, S.; Meti, S.; Anandalli, M.; Badiger, H.; Bhajantri, R.F.; Pratheek, L.; Muhiuddin, M.; Rahman, M.R.; Hegde, B.G.Herein, we report the synthesis of ytterbium (Yb) (with concentration x = 0.01, 0.015, 0.02, 0.025 and 0.03) doped in to nickel cobalt ferrite (NCYFO: YbxNi0.5Co0.5Fe2-xO4) nanoparticles at temperature 500 °C with phase pure spinel using solution combustion technique. The phase purity and effect of doping on NCYFO complex oxide on structural, thermal, magnetic and dielectric properties have been determined by various characterization techniques. The FTIR data reveal that strong metal oxide linkages can be observed in the tetrahedral and octahedral sites at wavenumbers 460 to 410 cm−1 and 595 to 540 cm−1. The X-ray diffraction (XRD) studies confirmed the spinel structure. The crystallite sizes and lattice parameters were estimated to be in the range of 31 to 22 nm and 8.32 to 8.35 Å, respectively. The X-ray photoelectron spectroscopy (XPS) study confirmed that the increase in Yb concentration results in accumulation of Yb in the grain boundaries of NCYFO in the form of Yb2O3. The thermal stability of nanoparticles were investigated using TGA/DSC method. Transmission Electron microscopy (TEM) studies and Field emission scanning electron microscopy (FESEM) used to study the particle size distribution and elemental composition within the nanomaterial. In addition, the dielectric properties, such as, dielectric constant and dielectric loss were investigated for all the NCYFO nanomaterial. The saturation magnetization of the NCYFO is determined using vibrating sample magnetometer (VSM) analysis and is maximum for x = 0.03 (Ms = 97.56 emu/g) sample. The high magnetic behaviour and better dielectric properties of the NCYFO nanomaterials are suitable for electro-magnetic applications. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.