  The nanocrystalline Ni0.7Cu0.3AlxFe2-xO4 (x=0.00: 0.02: 0.10) is prepared
through the sol-gel autocombustion route.Both XRD and Rietveld confirm the
single-phase cubic spinel structure of the investigated materials.Other
structural parameters refined by the Rietveld refinement analysis are
corroborated to single-phase cubic spinel formation of the NPs.Leveraging a
vibrating sample magnetometer (VSM) the consequence of Al3+ substitution on the
magnetic parameters is studied.The saturation magnetization (MS) and Bohr
magneton are found to decrease with Al3+ substitution.The Remanence ratio and
coercivity (HC) are observed to be very low suggesting the materials are soft
ferromagnetic.First-principle calculations were carried out using the density
functional theory (DFT) to demonstrate the optoelectronic behavior of the
materials.The electronic bandgap is found low as Eg=2.99eV for the explored
materials with observing defect states at 0.62eV.The optoelectronic properties
of Al3+ substituted Ni-Cu ferrite NPs have been characterized through the DFT
simulation for the first time, demonstrating their potentiality for
optoelectronic device applications.The materials' optical anisotropy is
observed along the x-axis, which manifests their tunability through
light-matter interaction.
