Preparation Of BST Nanotube And Its Infrared Absorption Properties

BaxSr1-xTiO3 (BST) materials regarded as one kind of ferroelectrics without Pb have perovskite structure. Because they have excellent ferroelectric, pyroelectric, and dielectric properties, the BST materials are widely used in fabricating dynamic random access memorys, pyroelectric detectors, microwave resonant devices and so on. But nowadays, the vast majority studies on BST materials are about their films, powder and bulks, the nanostructures of BST materials are very rare. Ba0.6Sr0.4TiO3 nanotubes were fabricated successfully by sol-sel method with the through-hole anodic aluminum oxide (AAO) template for the first time so far as we know. This fabrication method is easy to realize at low cost because that the through-hole AAO template and the BST sol can be acquired easily at low cost, so it is very valuable in the fabrication of other similar nanostructures. First, the well aligned through-hole anodic aluminum oxide template was fabricated by a two-step anodization method, the thickness and pore size of which are about 16 ?m and 75 nm, respectively; second, the steady BST sol was prepared; and finally, the BST sol was introduced into the through-hole AAO template by dipping and spinning; finally, the samples were fired in air at 650? for 1 hour to get BST nanotubes. SEM results show that the length, external diameter and inner diameter of the BST nanotubes are about 16 ?m,75 nm and 50 nm, respectively. Measurements of BST nanotubes give results highly matched with that of the through-hole AAO template. EDS results prove that the nanotubes contain Ba, Sr and Ti. XRD results reveal that the BST nanotubes are cubic perovskite structure, and grow mainly along (110) crystal orientation. FTIR results display that in 1350-1650 cm-1 waveband, AAO/BST nanotubes composite structure has two obvious absorption peaks which are respectively at 1470 and 1550 cm-1, but BST film do not has; the absorption property of composite structure is about two times of the pure through-hole AAO membrane; finally, the possible reasons of these phenomena about infrared absorption are discussed.