Structural, optical, thermal and magnetic properties of nickel calcium and nickel iron co-doped ZnO nanoparticles

Zinc oxide (ZnO), Nickel calcium co-doped ZnO (ZNCO) and Nickel iron co-doped ZnO (ZNFO) nanoparticles (NPs) were prepared by co-precipitation method. The particles were characterized by XRD, FT-IR, HR-SEM and their chemical compositions were identified by EDX spectra. The synthesized ZnO, ZNCO and ZNFO NPs exhibited wurtizite hexagonal structure. HR-SEM image analysis showed the formation of nanoflake and spindle like structure for ZnO, ZNCO and ZNFO NPs. The characteristic bands were observed at 432, 445 and 455 cm^-1 for ZnO, ZNCO and ZNFO NPs, respectively. The band gap was estimated to be 3.84 eV, 3.91 and 4.09 eV for all ZnO NPs. The thermal behavior of the synthesized nanoparticles had been studied using TG-DTA analysis. From the magnetic studies, the NiFe co-doped ZnO (ZNFO) exhibited higher saturation magnetization values than that of NiCa co-doped ZnO (ZNCO) NPs.