Mössbauer and magnetic studies of Fe-doped ZnO nanoparticles prepared by solution co-precipitation method

A series of Zn 1 − x ${}_{1-x}$ Fe x O ( x = 0 $x=0$ , 0.015, 0.045, 0.075) nanoparticles were synthesized using the solution co-precipitation method, and their structural and property characteristics were investigated. X-ray diffraction (XRD) analysis revealed that all Zn 1 − x ${}_{1-x}$ Fe x O samples exhibited a hexagonal wurtzite crystal structure with the P63mc space group. The introduction of Fe doping led to a slight lattice distortion in the samples. The morphology of the nanoparticles, including polydispersion and agglomeration, as well as the presence of the second phase ZnFe 2 O 4 , was examined by scanning electron microscope (SEM) and transmission electron microscope (TEM). UV–Vis diffuse reflectance spectroscopy demonstrated that the band gap of Zn 1 − x ${}_{1-x}$ Fe x O lies between 3.152 and 3.163 $$ eV. With the increase in Fe ion doping, the band gap shows a slight decreasing trend. Mössbauer spectroscopy revealed that iron ions in the nanoparticles existed in a trivalent state and exhibited two different configurations: One involved iron replacing zinc without creating a vacancy, while the other involved iron substituting zinc with a vacancy. The ferromagnetic nature of the Fe-doped samples can be attributed to the exchange interaction between two Fe 3 + ${}^{3+}$ ions mediated by the F-center mechanism.