Effect of synthesis parameters on crystal structure and magnetic properties of cobalt zinc ferrite (Co_(0.5)Zn_(0.5)Fe2O4) nanoparticles

摘要

Co_(0.5)Zn_(0.5)Fe2O4nanoparticles have been successfully synthesized by coprecipitation method with varying NaOH concentrations and synthesis temperatures. X-ray diffraction (XRD) analysis confirmed that Co_(0.5)Zn_(0.5)Fe2O4 nanoparticles have spinel cubic crystal structure with crystallite size ranging from 7.9 to 21.4 nm. The crystallite size increase relatively by increasing NaOH concentration and synthesis temperature which related to the nucleation and crystal growth mechanism of nanoparticles during synthesis. The transmission electron microscope (TEM) image showed that the sample was aglomerated. The selected area electron diffraction (SAED) image showed the diffraction ring as representation of miller plane and confirmed that sample was polycrystalline. Magnetic measurement indicated that Co_(0.5)Zn_(0.5)Fe2O4 nanoparticles shows ferimagnetic behaviour and tend to be superparamagnetic with decreasing crystallite size. The increase in coercivity and maximal magnetization also have been found by increasing NaOH concentration and synthesis temperature. It is attributed to single domain existence and an increasing of crystallinity degree. The Fourier transform infrared spectroscope (FTIR) spectra also confirmed the existence of symmetric stretching vibration bands of metal ions near 563-609 cm~(-1) and 316-493 cm~(-1) in tetrahedral and octahedral sites, respectively.