Study On Electrochemical Regulation And Magnetic Properties Of Samarium Nickel Alloy Nanotubes

Compared with the simple substance metal nanometer materials, the metal alloy nanometer materials have many unique structures and characters, such as high coercivity, large squareness ratio. So researchers pay more attention to them recently. The method of anodic aluminum oxide (AAO) template is widely applied to the fabrication of nanotubes due to its low cost.In this experiment, AAO templates with uniform pores were obtained by two step oxidation. Using VERSASTAT3electrochemical workstation, Sm-Ni alloy nanotubes with different atomic ratio have been fabricated into the AAO template by direct current electrodeposition method. The patterns of AAO template were observed by atomic force microscope (AFM), the basic morphology of Sm-Ni alloy nanotubes was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), the crystal structure of nanotubes was studied by X-ray diffraction (XRD), the composition of nanotubes was confirmed by electron dispersive spectroscopy (EDS), and the magnetic properties of nanotubes were measured by vibrating sample magnetometer (VSM).In this paper, a series of AAO templates were obtained in0.3mol/L oxalic acid electrolyte under oxidation voltage of40V,50V, and60V, respectively. The result shows the order degree of pores decreases as the voltage increases. A series of AAO templates were obtain when the second oxidation time is10h,11h,12h, and13h, respectively. The results show that the pores diameter of all templates is about68nm and the order of the templates increases with the second oxidation time increasing. The percentage of Sm and Ni atoms can been regulated by the deposition potential. Selected area electron diffraction (SAED) patterns and XRD pattern of Sm-Ni alloy nanotubes illustrate that all the nanotubes are amorphous. After annealing at600℃for2h in nitrogen, the alloy nanotubes are still amorphous by means of XRD analysis, however, their magnetism have a great improvement. There is apparent magnetic anisotropy in Sm-Ni alloy nanotubes and the easy magnetization axis is parallel to the axis of nanotubes.