Nano-mn-zn Ferrite Doped Structure, Performance Studies

The development of soft magnetic materials were reviewed in this paper. The developing tendency of ceramics and it's problems to be solved were depicted briefly. Nano-magnetic material is the main domain in material study in future. As an important sort of magnetic, MnZn-ferrites must have a better prospect.The La3+-, Nd3+-, Ti4+- and multi-element-doped nanoscale particles of MnZn ferrites were fabricated by using a hydrothermal method. It was studied that the grain shape % grain size and structure of nano-MnZn ferrite powders were affected by the impurities; and the changes of properties of nano-MnZn ferrites with different content Ti4+ and La3+ ions were investigated importantly.The results showed that the the crystalline orientations and increment of nano-MnZn ferrites were affected by impurity La3+ ions. The orientations of crystalline growth for nano-MnZn ferrites changed and the growth of their crystals was promoted with doping certain La3+ ions. Their shape of nano-MnZn ferrite crystals was transformed from cube to hexagons. But the impurity Ti4+ ions had not obvious effect on the size and shape of nano-MnZn ferrite crystals; while the effect on the grain size for Ti4+-doped sample was obvious and the peak of grain size distributing curve of it was out of 100nm when x>1.0%. The intensity of spinel characteristic apexes in IR for Ti4+-doped nano-MnZn ferrite was amplified obviously and the intrinsic ion distributing was influenced by the impurity Ti4+ions via IR and XRD analyzing. The apex (577.17cm"1) of nano-MnZn ferrites was broader and moved to lower frequency than that of the great crystals (>lum) and the apex (448.30cm-1) of nano-MnZn ferrites was splited into a group of apexes.It was found that the variation of initial permeability with temperature for the samples decreased and it's even district was broadened because of the impurities Ti4+, La3+ ions, but the even district of La3+-doped samples was broader than that of the Ti4+-doped; while theinitial permeability(ui) for Ti4+-doped Mn-Zn ferrites increased more obviously. The magnetic loss tangent decreased due to certain content impurities La3+, Ti4+ ions, which cut the loss down efficiently. The saturation magnetization Ms and Curie temperature Tc of the samples with La3+ or Ti4+ were lower than that of the undoped because La3+ Ti4+ ions were not magnetic.In addition, the density of nano-MnZn ferrites was affected by La3+ ions, which was useful for the increase of electrical resistivity.At last, a cationic vacancy model was established for the first time to study the behavior of doping on base of analyzing the microstmcture and properties of the samples.