Studies On Magnetic Ferrite Zn_xFe_3-XO₄ By X-Ray Photoelectron Spectroscopy

The material of magnetic ferrite has been widely applied in many fields because of its exceptive magnetism and electronic structure. Recently, in order to improve their physical properties and their applications, a new surge of interest in ferrites has been initiated. It was found that the magnetic properties of ferrite were strongly dependent on the state of chemical order and, in particular, on the cation site occupancy in the material. To understand the cation distribution in spinel ferrites and their effects on the resulting magnetic properties is still a challenging problem.The subject of zinc ferrites (ZnFe2O4) has been frequently studied because of its intriguing magnetic properties, the different magnetic properties of ZnxFe3-xO4 (x < 1) have drawn our interests. In this work, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) are important techniques for our studies. A series of samples ZnxFe3-xO4 (ZnxFe3-xO4, x = 0, 1/6, 1/3, 1/2, 2/3)prepared by the chemical coprecipitation method were the object we studied. X-ray diffraction (XRD) demonstrated all the samples of ZnxFe3-xO4 had spinel structures as the pure Fe3O4. The magnetic hysteresis loops of ZnxFe3-xO4 obtained from VSM indicated that there existed a maximum in the saturation magnetization of the samples with x increased. In order to explain this phenomenon, we studied the chemical environment of the ions. The detail work of this thesis as follows:Firstly, the X-ray photoelectron spectrums of the samples were measured and the data were analyzed. The features of Fe 2p, Zn 2p and O 1s were recorded. The lines of O 1s indicated the oxygen stoichiometry was a constant. The lines of Fe 2p indicated the peak positions slightly shift to higher binding energy side as the amount of Zn doped into Fe3O4 increased. Then we deconvolved the broad spectra of Fe 2p peaks of ZnxFe3-xO4, through fitting, the percentage of each peak area (PA), the ratio of Fe atoms at different sites and the percentages of Zn atoms at A-sites and B-sites were calculated. The binding energies of Zn 2p peaks show that Zn 2p peak positions of the samples shift very little, so the Auger electron spectroscopy (AES) should be analyzed.Secondly, AES of the samples were measured and the data were analyzed. Zn L3M45M45 Auger peaks were analyzed; we found the L3M45M45 peak shifted to higher kinetic energy side with the amount of Zn doped increasing. Then we calculated the Auger parameters of the samples and compared them to the empirical values, it can be found the values of the sample with x = 1/6 were closest to franklinite ZnFe2O4 while the values of the sample with x = 2/3 were most different from...