Synthesis and Magnetic Characterization of Nickel Ferrite Nanowire Arrays Doped with Manganese

摘要

The spinel ferrite system Ni_(1-x)Mn_xFe_2O_4 (x = 0.0, 0.25, 0.5, 0.75) nanowire arrays with an average diameter of about 80 nm, have been synthesized into nanopores of anodic aluminum oxide (AAO) template using the sol-gel technique. X-ray diffraction analysis shows the formation of single-phase nickel manganese ferrites. Scanning electron microscopy and transmission electron microscope images indicate that the nanowire arrays are composed of prolate spheroids with different crystal orientations. Magnetic measurements show that the saturation magnetization (M_s) of nickel ferrite nanowire arrays is lower than that of bulk ones. But the M_s of the samples doped with Mn are greater than that of bulk ones. We do not observe obviously easy magnetization direction of all nanowire arrays. The possible reasons that are responsible for the composition dependence of the properties are discussed.