Preparation and magnetic properties of Y₃Fe₅O ₁₂ nanoparticles doped with the gadolinium oxide

Gd³⁺-substituted garnet nanoparticles Y_{3- x}Gd_xFe₅O₁₂ (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) were fabricated by a sol-gel method and their crystalline structures and magnetic properties were investigated by using X-ray diffraction (XRD), IR spectroscopy and vibrating sample magnetometer (VSM). The XRD patterns of Y_3-xGd_xFe₅O₁₂ have only peaks of the garnet structure and the sizes of particles range from 34 to 67 nm. Results of VSM show that the special saturation magnetization of Y _3-xGd_xFe₅O₁₂ (0<x≤1) particles are not only obviously less than pure YIG, but also decrease with increasing Gd concentration (x) in a linear manner. Meanwhile, it is observed that with the enhancement of the surface spin effects, the saturation magnetization rises as the particle size is increased.