Granular superconductivity in metallic and insulating nanocrystalline boron-doped diamond thin films

B L Willems (1, 2) , G Zhang (1) , J Vanacken (1) , V V Moshchalkov (1) , S D Janssens (3) , K Haenen (3, 4) , P Wagner (3, 4)

1 INPAC-Institute for Nanoscale Physics and Chemistry
2 Facultad de Ciencias Fsicas
3 Institute for Materials Research ( IMO )
4 Division IMOMEC

The low temperature electrical transport properties of nanocrystalline boron-doped diamond thin films (b-NCD) have been found to be strongly affected by the system's granularity. The important differences between the high and low temperature behavior are caused by the inhomogeneous nucleation of superconductivity in the samples. In this review we will discuss the experimental data obtained on several b-NCD thin films, which were studied by either varying their thickness or boron concentration. It will be shown that the low temperature properties are influenced by the b-NCD grain boundaries as well as by the appearance of an intrinsic granularity inside these granules. Moreover, superconducting effects have been found to be present even in insulating b-NCD films and are responsible for the negative magnetoresistance regime observed at low temperatures. On the other hand, the low temperature electrical transport properties of b-NCD films show important similarities with those observed for granular superconductors.

Mots clés: Physical Sciences

B L Willems, G Zhang, J Vanacken, V V Moshchalkov, S D Janssens, et al.. Granular superconductivity in metallic and insulating nanocrystalline boron-doped diamond thin films. Journal of Physics D: Applied Physics, 2010, 43 (37), pp.374019. ⟨10.1088/0022-3727/43/37/374019⟩. ⟨hal-00569708⟩