Magnetic properties of Nd-Y3Fe5O12 nanoparticles

Nb3+-substituted garnet nanoparticles Y3-xNdxFe5O12 (x = 0.0, 0.5, 1.0, 1.5, and 2.0) were fabricated by a sol-gel method and their crystalline structures and magnetic properties were investigated by using X-ray diffraction (XRD), thermal analysis (DTA/TG), and vibrating sample magnetometer (VSM). The XRD patterns of Y3-xNdxFe5O12 have only peaks of the garnet structure and the sizes of particles range from 34 to 70 nm. From the results of VSM, it is shown that when the Nd concentration x ( 1.0, the saturation magnetization of Y3-xNdxFe5O12 increases as the Nd concentration (x) is increased, and gets its maximum at x = 1.0, but when x ( 1.0, the saturation magnetization decreases with increasing the Nd concentration (x), this may be due to the distortion of the microstructure of Y3-xNdxFe5O12, which leads to the decrease of the effective moment formed by Fe3+. Meanwhile, it is observed that with the enhancement of the surface spin effects, the saturation magnetization rises as the particle size is increased.