Magnetic properties of Ce,Gd-substituted yttrium iron garnet ferrite powders fabricated using a sol–gel method

Y3−x−yCexGdyFe5O12 (x = 0–0.1, y = 0–1.0) nanoparticles were fabricated by a sol–gel method. The crystalline structures and magnetic properties of samples were investigated by X-ray diffraction (XRD), scanning probe microscopy (SPM), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM). The XRD patterns of Y3−x−yCexGdyFe5O12 have only peaks of the garnet structure and the mean size range from 42 to 65 nm. The particle's size observed for all the samples analyzed by SPM are in good agreement with these data from XRD. The particle's size ranged from 50 to 70 nm, at the same time, there are small amount of reunited particles can be observed. XPS for Y2.9Ce0.1Fe5O12 gives two peaks at 885.15 and 905.15 eV attributing to Ce3+3d5/2 and 3d3/2, respectively. The results confirm the valence state of Ce atoms being +3. Results of VSM show that the saturation magnetization is increased with increasing Ce content (x) and is decreased with increasing the Gd concentration (y) in a linear manner. The saturation magnetization is increased with increasing the particle's size.