2008/04/30 by S. P. Chockalingam, Madhavi Chand, John Jesudasan +2 · 3 citations
Engineering · Physics and Astronomy · #Physics of Superconductivity and Magnetism #Superconducting Materials and Applications #Superconductivity in MgB2 and Alloys #cond-mat.dis-nn #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.77.214503
published as Physical Review B 77, 214503 (2008) · ps files with figures (accepted for publication in Phys. Rev. B)
arxiv created 2008/05/10 · openalex publication_date 2008/06/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We have measured the magnetotransport properties and Hall effect of a series of epitaxial NbN films grown on (100) oriented single crystalline MgO substrate under different conditions using reactive magnetron sputtering. Hall effect measurements reveal that the carrier density in NbN thin films is sensitive to the growth condition. The carrier density increases by a factor of 3 between the film with highest normal state resistivity (\ensuremathρn\ensuremath∼3.83 \ensuremathμ\ensuremathΩ m) and lowest transition temperature (Tc\ensuremath∼9.99 K) and the film with lowest normal state resistivity (\ensuremathρn\ensuremath∼0.94 \ensuremathμ\ensuremathΩ m) and highest transition temperature (Tc\ensuremath∼16.11 K), while the mobility of carriers does not change significantly. Our results show that Tc of NbN is governed primarily by the carrier density rather than disorder scattering. By varying the carrier concentration during growth, we can vary the effective disorder (kFl) from the moderately clean limit to the dirty limit, which makes this system ideal to study the interplay of carrier density and disorder on the superconducting properties of an s-wave superconductor.