Investigation of Structural, Magnetic and Electrical Properties of Chromium Substituted Nickel Ceramic Nanopowders

Nano-ceramic of NiCrxFe2-xO4 (0.1 ≤ x ≤ 1.0) ferrites were synthesized by citrate-gel auto combustion method. The structural parameter such as lattice parameter, X-ray density, bulk density and porosity variations with Cr doping were studied. The average crystallite size is in the range 8.5–10.5 nm. The surface morphology and elemental analysis was studied with SEM (EDAX) spectrum and the structural information analyzed with FTIR spectra. Magnetic properties were discussed with Cr3+ion concentration. Electrical parameters like dc resistivity and drift mobility were reported with function of temperature and dopent concentration from room temperature to well beyond Curie temperature and explained with hopping mechanism between Fe2+↔Fe3+ ions. The activation energies in ferri and para magnetic regions were investigated. Dielectric parameters like dielectric constant, dielectric loss and ac conductivity were investigated variation with frequency and composition

Investigation of structural, magnetic, and electric properties of Ni-Cr-Bi nano ferrites an effect of rare earth cerium element by sol-gel auto combustion method

In the present study, the rare-earth Ce3+ ion substation influences Ni-Cr-Bi nanoferrites with the chemical formulation Ni0.5Cr0.2Bi0.3Cex3+Fe2-xO4 (x = 0.00, 0.03, 0.06, and 0.09) synthesized via the citrate-induced sol–gel auto combustion method. X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FESM), high-resolution transmission electron microscopy (HRTEM), vibrating sample magnetometer (VSM), and dielectric studies. The XRD test confirmed that the structure was a single-phase face-centered cubic (FCC) spinel with an Fd3m space group. The crystallite size obtained by the XRD pattern is in the range from 36.43 nm to 36.73 nm with Ce3+ content, which indicates the formation of nanocrystalline samples. The lattice constant was increased from 4.168 Å to 4.191 Å. The FESEM pictures show the materials' morphology as agglomerations of spherical-shaped particles with a grain size of 22.46 nm to 31.46 nm. The HRTEM picture showed a spherical particle size of 55.32 nm. The saturation magnetization (Ms) was observed for x = 0.09 composition as 69.87 (emu/gm). The coercivity and remanence varying increased from 84.57 Oe to 164.68 Oe and 6.09 emu/gm to 7.88 emu/gm. The frequency variation of the dielectric constant and loss tangent exhibit space charge polarization as a phenomenon governing the dielectric behavior of the ferrites reveals the observed ac-conductivity in the frequency range of 5 MHz to 25 GHz. In addition to the main role that grain boundaries play in the conduction process, the impedance analysis showed that the samples being studied also had electrical relaxations