School of Physics Science and Technology, Soochow University, Suzhou 215000, China.
Nat Commun. 2011 Aug 16;2:428. doi: 10.1038/ncomms1438.
The formation of carbon nanotube and superconductor composites makes it possible to produce new and/or improved functionalities that the individual material does not possess. Here we show that coating carbon nanotube forests with superconducting niobium carbide (NbC) does not destroy the microstructure of the nanotubes. NbC also shows much improved superconducting properties such as a higher irreversibility and upper critical field. An upper critical field value of ~5 T at 4.2 K is much greater than the 1.7 T reported in the literature for pure bulk NbC. Furthermore, the aligned carbon nanotubes induce anisotropy in the upper critical field, with a higher upper critical field occurring when the magnetic field is parallel to the carbon nanotube growth direction. These results suggest that highly oriented carbon nanotubes embedded in superconducting NbC matrix can function as defects and effectively enhance the superconducting properties of the NbC.
碳纳米管和超导复合材料的形成使得产生新的和/或改进的功能成为可能，而这些功能是单个材料所不具备的。在这里，我们表明，用超导碳化铌（NbC）涂覆碳纳米管森林不会破坏纳米管的微观结构。NbC 还显示出了改进的超导性能，例如更高的不可逆性和上临界场。在 4.2 K 时约为 5 T 的上临界场值远大于文献中报道的纯块状 NbC 的 1.7 T。此外，排列整齐的碳纳米管在上临界场中诱导各向异性，当磁场平行于碳纳米管生长方向时，上临界场更高。这些结果表明，嵌入超导 NbC 基体中的高度取向的碳纳米管可以作为缺陷，有效地增强 NbC 的超导性能。
