Highly aligned carbon nanotube forests coated by superconducting NbC

G. ZOU; H. LUO; S. BAILY; Y. ZHANG; N. HABERKORN; J. XIONG; E. BAUER; T. MCCLESKEY; A. BURRELL; L.CIVALE; Y. T. ZHU; J. L. MACMANUS-DRISCOLL; Q. X. JIA

Nature Communications

Nature Publishing Group

Lugar: London; Año: 2011 vol. 1438 p. 1 - 5

2041-1723

Both carbon nanotubes (CNTs) and superconductors (SCs) are technologically important materials. The formation of CNT/SC composites makes it possible to produce new or improved functionalities that an individual material does not possess. Here we, for the first time in the field, report the integration of superconducting NbC with the highly aligned CNT forests using a chemical solution approach. The formation of superconducting NbC coating on the CNT forests does not destroy the microstructure of CNTs. Importantly, NbC shows much improved superconducting properties such as higher irreversibility field (Hirr) and upper critical field (Hc2). A value of Hc2 around 5 T at 4.2 K is much greater than 1.7 T for the pure NbC reported in the literature. Moreover, the aligned CNTs induce anisotropy in Hc2, with higher Hc2 when the magnetic field is parallel to the CNT growth direction. These results suggest that highly oriented CNTs embedded in superconducting NbC can function as defects and effectively enhance the superconducting properties of the NbC. It should be noted that introduction of artificial defects into high-temperature superconducting YBa2Cu3O7-x (YBCO) has been broadly investigated to modify the superconducting properties. For example, much improved superconducting properties of YBCO have been accomplished through introducing columnar defects by high-energy irradiation and volume defects by inclusion of nanoparticles or of self-assembled vertically aligned “bamboo” arrays.