Preparation And Study Of Porous Anodic Aluminum Oxide Templates And Magnetic Nanotubes Of The Sm-Fe Alloy

Magnetic nanomaterials have been applied to ultra-small permanent motors, magnetic media, and magnetic nanometer devices due to their many outstanding characters, such as high coercivity, large squareness ratio, and so on. In this paper, Sm-Fe nanotubes have been successfully fabricated in nano-pores of the self-made anodic aluminum oxide (AAO) templates by DC electrochemical deposition method. The crystalline structure and morphology of nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM), and the compositions were confirmed by energy dispersive spectrometry (EDS). The magnetic properties of samples were measured by vibrating sample magnetometer (VSM).Because AAO templates are easily prepared, their pore size is controllable, and their chemical properties are stable, they have been widely used. In this paper, the porous AAO template is obtained by the two-step anodic oxidation method. We studied the influence of the oxidation time and the different oxidation liquid on AAO template. The results show the longer oxidation time is, the larger the pore of alumina template is. The AAO templates were prepared in sulfuric acid solution, phosphoric acid solution and oxalic acidsolution, respectively. The uniformity of AAO template prepared in oxalic acidsolution is the best.The Sm-Fe alloy nanotubes, with the diameter of35nm, the length of40μm,were fabricated into self-made AAO template. The nanotubes have the amorphous structure. The atomic ratio of the samarium and iron in nanotube alloys could be controlled by the concentration of the electrolyte. Sm-Fe nanotubes have the obvious magnetic anisotropy, and the easy magnetization axis is parallel to the axis of the nanotubes. The coercivity of Sm-Fe nanotubes is greater when magnetic field is parallel to nanotubes compared with perpendicular to nanotubes. With the decrease of the deposition potential, the length-diameter ratio, the shape anisotropy and the coercivity of nanotubes increase.