Achieving the Theoretical Depairing Current Limit in Superconducting Nanomesh Films

• Published in: Nano letters Vol. 10; no. 10; pp. 4206 - 4210
• Main Authors: Xu, Ke, Cao, Peigen, Heath, James R.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 13.10.2010
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Mesoscopic and nanoscale systems; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Quantum wires; Superconducting films and low-dimensional structures; Superconductivity; Superconductors; nanomaterials; electronic materials; nanofabrication; Superconducting thin films; Critical current density; Temperature dependence; Superconductivity; Niobium; Penetration depth; Thin films; Superconducting films; Calcium nitride; Beryllium; Nanowires; Nanostructured materials; Temperature fluctuation
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl102584j

We show the theoretical depairing current limit can be achieved in a robust fashion in highly ordered superconductor nanomesh films having spatial periodicities smaller than both the superconducting coherence length and the magnetic penetration depth. For a niobium nanomesh film with 34 nm spatial periodicity, the experimental critical current density is enhanced by more than 17 times over the continuous film and is in good agreement with the depairing limit over the entire measured temperature range. The nanomesh superconductors are also less susceptible to thermal fluctuations when compared to nanowire superconductors. T c values similar to the bulk film are achieved, and the nanomeshes are capable of retaining superconductivity to higher fields relative to the bulk. In addition, periodic oscillations in T c are observed as a function of field, reflecting the highly ordered nanomesh structure.