Upper critical magnetic field and vortex-free state in very thin epitaxial δ-MoN films grown by polymer-assisted deposition

• Published in: Superconductor science & technology 2013-10, Vol.26 (10), p.105023-7
• Main Authors: Haberkorn, N, Zhang, Y Y, Kim, Jeehoon, McCleskey, Thomas M, Burrell, Anthony K, Depaula, R F, Tajima, T, Jia, Q X, Civale, L
• Format: Article
• Language: English
• Subjects: Coherence; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Critical currents; Cross-disciplinary physics: materials science; rheology; Deposition; Epitaxial growth; Exact sciences and technology; Fluid flow; Magnetic fields; Materials science; Other materials; Penetration depth; Physics; Properties of type I and type II superconductors; Specific materials; Superconductivity; Thin films; Transition temperature variations; Vortices
• ISSN: 0953-2048; 1361-6668
• DOI: 10.1088/0953-2048/26/10/105023

We measured the thickness dependence of the superconducting properties in epitaxial δ-MoN thin films grown on α-Al2O3(001) substrates by polymer-assisted deposition. Our results indicate that the superconducting properties such as the upper critical field (μ0Hc2 10 T) and the superconducting critical temperature (Tc = 12.5 K) are thickness independent for films thicker than ∼36 nm. By measuring the critical current density (Jc) in the vortex-free state, which coincides with the depairing current density (J0), we estimate that films thicker than ∼36 nm have a coherence length ξ(0) = 5.8 ± 0.2 nm and penetration depth λ(0) = 420 ± 50 nm. We found that it is possible to enhance the Hc2(0) values to close to 10 T without any appreciable reduction in Tc.