Effects of La~(3+) doping on MnZn ferrite nanoscale particles synthesized by hydrothermal method

摘要

MnZn ferrite nanoscale particles were synthesized by hydrothermal method. The effects of amount of addition La~(3+) on the products were discussed. The product was characterized by X-ray diffraction (XRD) and trans-mission electron microscope (TEM). The results show that the sample with 0. 2% La~(3+) (mass fraction) or without La~(3+) has only spinel phase, but the sample with mass fraction of La~(3+) exceeding 0. 4% posses second phase besides the spinel one; and the nano-MnZn ferrites change from cube to hexagon when the mass fractions of La~(3+) is up to 1.2%. TEM image of the sample with 1.2% La~(3+) indicates that the homogeneous hexagonal crystal is obtained and the particles are larger than those of undoped; the addition of La~(3+) has great influence on the crystallization of hydrothermal process and can change the shape of particles and improve their growth. The saturation magnetization of the sample with 1.2% La~(3+) (2. 64 A · m~2 · kg~(-1)) is lower than that of undoped (17. 54 A · m~2 · kg~(-1)) and it behaves superparamagnetically.