Comparison the effect of co-precipitation and sol-gel techniques on the structural and magnetic attributes of ZnO and Zn(1-x)Fe0.05CoxO nanoparticles for attaining room temperature ferromagnetism (RTFM)

Abstract

In current study, ZnO and Fe/Co co-doped ZnO (Zn1-x Fe0.05 Cox O where x = 0, 0.005) nanoparticles were prepared by using two different methodologies: sol gel method and coprecipitation method. The structural properties were determined by X-Ray diffraction technique which verifies the hexagonal wurtzite structure of prepared nanoparticles. Crystallite size varies from 18.68-37.43 nm for the samples synthesized by co-precipitation method and it varies from 19.97-38.45 nm for sol-gel method. Fourier transform infrared transmittance spectra were used to investigate the type of functional groups present in all the prepared nanoparticles. The UV-Visible absorption spectroscopy was employed to investigate the optical properties of ZnO and doping of Fe/Co in ZnO semiconducting host. The energy band gap varies from 3.03 - 3.68 eV for the samples synthesized by coprecipitation method and for sol-gel method, it ranges from 3.13 - 3.86 eV, by increasing dopant concentration. Vibrating sample magnetometer was used to inquire the magnetic behavior of synthesized nanoparticles which shows the weak ferromagnetic behavior of the doped nanoparticles prepared by both the techniques. Samples prepared by co-precipitation method showed higher values of saturation magnetization and coercivity as compared to the samples prepared by the sol-gel method. In comparison of two synthesis techniques, a slight change was observed in the particle size, energy band gap and magnetization values. The improved optical and magnetic behavior favors the co-precipitation method rather than sol gel method for obtaining room temperature ferromagnetism for practical applications in spintronics field.