Upper Critical Magnetic Field And Vortex-Free State In Very Thin Epitaxial Delta-Mon Films Grown By Polymer-Assisted Deposition

We measured the thickness dependence of the superconducting properties in epitaxial delta-MoN thin films grown on alpha-Al2O3(001) substrates by polymer-assisted deposition. Our results indicate that the superconducting properties such as the upper critical field (mu H-0(c2) approximate to 10 T) and the superconducting critical temperature (T-c = 12.5 K) are thickness independent for films thicker than similar to 36 nm. By measuring the critical current density (J(c)) in the vortex-free state, which coincides with the depairing current density (J(0)), we estimate that films thicker than similar to 36 nm have a coherence length xi(0) = 5.8 +/- 0.2 nm and penetration depth lambda(0) = 420 +/- 50 nm. We found that it is possible to enhance the H-c2(0) values to close to 10 T without any appreciable reduction in T-c.