Investigation of structural, morphological and magnetic study of Ni–Cu-substituted Li0.5Fe2.5O4 ferrites.

The Li_0.5-xNi_xCu_xFe_2.5−xO₄ for x = 0.00, 0.05, 0.10, 0.15, 0.20, and 0.25 were synthesized through the ceramic process following double sintering. Their structural, morphological, compositional, functional, and magnetic properties were analyzed with the help of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), and Vibrating Sample Magnetometer (VSM). The XRD patterns confirmed the single-phase spinel cubic structure. Lattice parameters increase from 8.3558 Å to 8.3615 Å. The increase in lattice parameter suggests the occupancy of Cu ions in the tetrahedral site, which can also be seen from the FTIR spectrum between 390 and 580 cm⁻¹. The SEM images show the grain size in the 2.28 to 3.75 μm, whereas the porosity ranges between 4.4% and 9.7%. A squareness ratio ranges between 0.18 and 0.24; the specific magnetization is between 26 and 42 emu/g. The coercivity is observed to range between 138 Oe and 145.75 Oe. The attached EDS spectra show the composition of the samples that agree well with their stoichiometry. The VSM study shows the occupancy of copper on both A- and B-sites as observed by cation distribution. Low electric and magnetic loss, low ac conductivity, and temperature-independent electric and magnetic properties are the fundamental properties of microwave devices that were obtained for the considered composition. Therefore, the substitution gives rise to the ferrite, which is appropriate for microwave devices. [ABSTRACT FROM AUTHOR]