Fabrication And Performance Of Rare Earth Oxide Nanotube Arrays

Fbrication of nanostructure materials have become an hot topic in the field of nanomaterials during the recent years. In this paper, we employed porous anodic alumina (AAM) as template with filtering at subatmospheric to fabricate a series of rare earth oxide nanotube arrays in the AAM template. The main research contents are as follows:1. The AAM template has been fabricated via two-step anodization with direct current in 0.3 M oxalic solution. The theoretical and influencing about the nano-array structure of AAM template are discussed.2. The Dy2O3 nanotube arrays have been synthesized in the AAM template by filtering at subatmospheric. The decomposition temperature of the precursor has been studied by thermal gravimetric analysis (TGA).The morphology, structure, composition, fluorescence and magnetism of the nanotubes have been investigated by using scanning electron microscopy (SEM),transmission electron microscopy (TEM), x-ray diffraction (XRD), energy dispersive spectra (EDS), selected area electron diffraction (SAED), fluoroscope and vibrating sample magnetometer (VSM), respectively. The result of EDS showed that the ratio of atomic percentage of Dy:O for Dy2O3 nanotube equals to 18.75:81.25, and the ratio of mass percentage of Dy O for Dy2O3 nanotube is 97.78:2.22. Fluorescence spectrum indicated that there is a fluorescence emission peak for Dy2O3 nanotubes at 587nm with 288nm light excited. The result of VSM showed that there is perpendicular anisotropy for Dy2O3 nanotube arrays at room temperature, and the easy magnetization direction is parallel to the direction of nanotube axis.3. The DyCoxOy nanotube arrays have been assembled in the pores of AAM template by the method of filtering at subatmospheric. The decomposition temperature of the precursor has been studied by TGA. The morphology of resulting samples has been characterized by SEM and TEM. The structure of the nanotubes has been characterized by SAED and XRD. The magnetism of DyCoxOy nanotube arrays has been studied by VSM. The results showed that the DyCoxOy nanotubes are amorphous, and the nanotubes are homogeneous, continuous and parallel from each other. The magnetization curve indicated that DyCoxOy nanotube arrays exhibits soft magnetic characteristics, and the easy magnetization direction is parallel to the direction of nanotube axis at room temperature.4. DyCoxZnyOz nanotube arrays have been fabricated in AAM by filtering at subatmospheric. The morphology and the crystal structure of DyCoxZnyOz nanotubes have been characterized by SEM,TEM,XRD,SAED and EDS, respectively. The results indicated that the DyCoxZnyOz nanotubes are amorphous, and the ratio of atomic percentage of Dy:Co:Zn:O is 4.86:1.67:1.70:91.77. The hysteresis loops characterized by VSM indicated that the easily magnetized direction of DyCoxZnyOz is parallel to the nanotube arrays and that there is magnetic anisotropy as a result of the shape anisotropy. DyCoxZnyOz nanotube arrays exhibited soft magnetic characteristics.5. SmNixOy nanotube arrays have been synthesized by the technique of filtering at subatmospheric assisted with AAM template. The morphology and the crystal structure of SmNixOy nanotubes are characterized by SEM,TEM,XRD,SAED and EDS, respectively. SAED and XRD indicated that the SmNixOy nanotubes are amorphous in structure. EDS showed that each SmNixOy nanotube contains three elements Sm, Ni and O, the ratio of atomic percentage of Sm:Ni:O is 5.85:1.62:92.53, and the ratio of mass percentage of Sm:Ni:O is 34.83:7.33:57.82, and there is a strong fluorescence emission peak for SmNixOy nanotubes at 383nm with 335nm light excited. VSM indicated that SmNixOy nanotube arrays with perpendicular anisotropy at room temperature, and the easy magnetization direction is parallel to the nanotube arrays.