Improving Dy, Ce, BhYIG phase formation and magnetic features via heat treatment and chemical composition

摘要

This paper focuses on the effect of Dy-substitution on the magnetic and structural behavior of Ce, Bi: YIG. In the current work, Fe_2O_3, Y_2O_3, CeO_2 and Dy_2O_3 fine powders were mixed at a stoichiometric portion and annealed at various temperatures from 1000 to 1420 °C in the air condition for different cycle times from 27 to 33 h. The phase identification, morphological study and magnetic performance were investigated using the Raman Spectroscopy (RS) and Fourier-Transform Infrared Spectroscopy (FTIR), X-ray diffraction analysis (XRD), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM), respectively. The X-ray diffraction pattern of Y_(2.55-x)Dy_xCe_(0.25)Bi_(0.20)Fe_5O_(12) (x = 0.2, 0.4, 0.6) (Sample A) confirms the impurity phase CeO_2. This category indicates that only a partial substitution of the Ce element is incorporated into the structure. For this reason, the ratio of the oxides and the heat treatment cycle were changed. The results revealed that the amount of CeO_2 phase decreases for the Sample B (Y_(2.7-x)Dy_xCe_(0.15)Bi_(0.15)Fe_5O_(12), x = 0.2, 0.4, 0.6, 0.8). To investigate the probability of a lower formation of the impurity phase (CeO_2), the Sample C (Y_(2.8-x)Dy_xCe_(0.10)Bi_(0.10)Fe_5O_(12), x = 0.2, 0.4, 0.6) with the lower amounts of Bi and Ce cations was considered. The data revealed that the amount of impurity phase slightly decreases as a result of the large ionic radii of Bi, Ce and Dy. The magnetic coercivity (Hc) was reduced from 25.06 for Sample B to 17.78 Oe for Sample C due to a reduction in the Bi and Ce elements and CeO_2 impurity phase as well. The saturation magnetization ascended from 31.47 for pure YIG to 35.15 emu/g for Sample B and to 33.76 emu/g for Sample C with the same value of the Dy content (x_(Dy) = 0.2).