Impact of Co2+ on the spectral, optoelectrical, and dielectric properties of Mg0.25Ni0.25Cu0.5?xCoxFe1.97La0.03O4 ferrites prepared via sol–gel auto-combustion route

Spinel ferrites are attaining huge importance in the modern era, due to their incredible properties, which means they widely used various fields. Therefore, this paper a cost-effective and environmentally friendly preparation of Mg0.25Ni0.25Cu0.5?xCoxFe1.97La0.03O4 (x = 0.0, 0.125, 0.25, 0.375, 0.5) via sol–gel auto-combustion method were carried out. How structural functional properties varied with Cu Co ratio was studied. It found that crystallite size (D) reduced from 47.2 27.6 nm as Co2+ increased x 0.0 0.5. While two major absorption bands including higher frequency band (?1) lower (?2) lie range 573.80–538.65 cm?1 470.37–405.65 belong spinel matrix. Five active Raman modes wave number 200–800 corresponds sublattices structure. The optical bandgap 0.85 eV 1.33 for 0.25 then observed gap 1.15 1.46 0.375 resistivity (?) minimum concentration at low temperature, while high temperature maximum doping 0.25. coefficient resistance percentage (TCR %) ?2.66%/K 513 K shown graphical abstract. At frequencies, impedance 0.125 0.375. These findings indicate as-prepared potential candidate optoelectrical bolometric devices.