Effect of Al3+ substitution on the synthesis, magnetic, and electrical properties of Ni0.3Zn0.5Co0.2Fe2−xAlxO4 spinel ferrites

The structural, magnetic, dielectric, and dc electrical resistivity properties of Al 3+ substituted Ni 0.3 Zn 0.5 Co 0.2 Fe 2− x Al x O 4 nano-ferrites with concentration x = 0.00, 0.05, 0.10, 0.15, and 0.20 samples are synthesised using the sol–gel auto-combustion synthesis route. The different properties of the synthesised nano-ferrites were studied using X-ray diffraction, field-emission scanning electron microscopy, Fourier transforms infrared spectroscopy, vibrating sample magnetometer, dielectric studies, and DC electrical resistivity techniques. The cubic spinel structure has been confirmed in the powder X-ray diffraction (XRD) spectra, with lattice constant values ranging from 8.385 to 8.323 Å and crystallite sizes decreasing with increasing Al 3+ content. Field emission scanning electron microscopy (FESEM) surface morphology analysis has shown a slight decrease in average grain size with increasing Al 3+ content. It was also found that the average grain size values 36.07, 42.27, 34.28, 32.14, and 26.57 nm. Fourier transform infrared spectroscopy (FT-IR) confirmed the formation of the spinel structure. According to vibrating sample magnetometer (VSM) investigations, the samples show isotropic ferrimagnetic domains. NiZnCo nano-ferrites partially doped with Al 3+ have been shown to result in calculated saturation magnetization values of 110.87 to 71.86 emu/g. The semiconducting nature was analyzed by measuring the DC electrical resistivity, which resulted in the DC conductivity increased with Al 3+ content. Al 3+ substitution also enhanced the dielectric behavior with a general decreased values but with non monotonic pattern. However, at the highest concentration of the dopant, the dielectric loss tangent (tan δ ) behaves wildly high values.