Magnetic cobalt-zinc ferrite/PVAc nanocomposite: synthesis and characterization

Abstract

Metal oxide nanoparticles are the subject of current interest because of their unusual optical, electronic, and magnetic properties. In this work, cobalt zinc ferrite ( Co_(0.3)Zn_(0.7)Fe_2O_4 ) nanoparticles have been synthesized successfully through redox chemical reaction in aqueous solution. The synthesized Co_(0.3)Zn_(0.7)Fe_2O_4 nanoparticles have been used for the preparation of homogenous polyvinyl acetate-based nanocomposite ( Co_(0.3)Zn_(0.7)Fe_2O_4/PVAc ) via in situ emulsion polymerization method. Structural, morphological and magnetic properties of the products were determined and characterized in detail by X-ray powder diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The XRD patterns of the Co_(0.3)Zn_(0.7)Fe_2O_4 confirmed that the formed nanoparticles are single crystalline. According to TEM micrographs, the synthesized Co_(0.3)Zn_(0.7)Fe_2O_4 nanoparticles had nano-needle morphology with an average particle size of 20 nm. The calculated coefficient of variation (CV) of nanoparticles diameters obtained by TEM micrographs was 16.77. The Co_(0.3)Zn_(0.7)Fe_2O_4 nanoparticles were dispersed almost uniformly in the polymer matrix as was proved by SEM technique. The magnetic parameters of the samples, such as saturation magnetization (M_s) and coercivity (H_c) were measured, as well. Magnetization measurements indicated that the saturation magnetization of synthesized Co_(0.3)Zn_(0.7)Fe_2O_4/PVAc nanocomposites was markedly less than that of Co_(0.3)Zn_(0.7)Fe_2O_4 magnetic nanoparticles. However, the nanocompoites exhibited super-paramagnetic behavior at room temperature under an applied magnetic field