Co1−xZnxFe2O4 (0≤x≤1) nanocrystalline solid solution prepared by the polyol method: Characterization and magnetic properties

Abstract Highly crystalline stoichiometric Co 1− x Zn x Fe 2 O 4 (0 ≤ x ≤ 1) nanoparticles were successfully synthesized by the polyol process. X-ray diffraction ( XRD ), X-ray fluorescence spectroscopy ( XRF ), transmission electron microscopy ( TEM ), infrared spectroscopy ( IR ), zero-field 57 Fe Mossbauer spectrometry and magnetic measurements using a SQUID magnetometer were employed to investigate the effect of the substitution of Zn 2+ ions for Co 2+ ones on the structure, and the magnetic properties of the cobalt ferrite, CoFe 2 O 4 . The unit cell parameter almost increases linearly with increasing Zn concentration, x , following Vegard's law. The red and blue shifts observed for the metal-oxygen ν 1 and ν 2 IR vibration bands, respectively, were consistent with the preferential entrance of Zn 2+ ions in tetrahedral sites. Besides, detailed magnetic investigation in correlation with the cation distribution has been reported. All the particles exhibit superparamagnetic behaviour at room temperature. In addition, the magnetic characteristics (blocking temperature, saturation magnetization, coercivity, Curie temperature) clearly depend on the chemical composition and cation distribution. Both the blocking temperature and Curie temperature decrease drastically with Zn composition, x , increase. Further, the saturation magnetization follows an almost bulk-like behaviour with values notably larger than that of the bulk, mainly attributed to cation distribution deviation.