Investigation of structural, optical and magnetic behavior of MAl2O4 (M= Zn and Co) nanoparticles via microwave combustion technique

Microwave combustion process is used to synthesize MAl2O4 (M = Zn and Co) spinel nanoparticles utilizing the fuel l-alanine. Synthesized samples were examined by techniques viz. XRD, HR-SEM, EDX, DRS-UV, PL, TG-DTA, FT-IR, XPS and VSM. The XRD confirmed the formation of cubic spinel structure with the average crystallite size of 14 nm and 11 nm for Cobalt and Zinc aluminate nanoparticles respectively. The morphology of CoAl2O4 (CAO) and ZnAl2O4 (ZAO) nanoparticles was observed by HR-SEM. EDX and XPS studies confirmed the formation of pure spinel aluminate structure. Further band gap values were estimated to be 3.35 and 5.45 eV for CAO and ZAO respectively. The PL spectra of CAO and ZAO nanoparticles were studied with an excitation wavelength of 235 and 205 nm. The strong absorption bands between 500-1100 cm-1 were linked to CAO and ZAO nanoparticles. TG-DTA analysis confirmed weight loss and exothermic transitions. The M − H loops revealed CoAl2O4 and ZnAl2O4 nanoparticles exhibited superparamagnetic behavior. •ZnAl2O4 and CoAl2O4 were synthesized by microwave combustion method.•Structural, morphological, optical, thermal and magnetic properties are studied.•ZnAl2O4 and CoAl2O4 nanoparticle exhibits a ferro and dia magnetic behavior.