Effects of La~(3+) Dopant on the Structure and Magnetic Properties of MnZn Ferrite Nano-Particles Synthesized by Hydrothermal Method

Nanoscale La3+-doped MnZn ferrite particles were synthesized by hydrothermal method, and the effects of La3+ ions on the crystallization behavior and magnetic properties of the sample were discussed. The samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the samples with mass ratio of La3+ dopant of x=0 and 0.2 % exhibit simple spinel phase structure, but a second phase appears for samples with x0.4% besides the spinel one. It is observed that the La3+ ions change the shape of particles and improve their growth. As a result, homogeneous hexagons crystalline is obtained. The saturation magnetization of La3+ doped samples is lower than that of the undoped, and even the sample with x=1.2% behaves superparamagnetically.