Flux pinning and improved critical current density in superconducting boron doped diamond films

The ability to carry transport current in a magnetic field is the most important aspect of a superconductor. We present a detailed analysis of the upper critical field (H _c2(0)) and vortex dynamics in superconducting boron doped diamond (BDD) films. H _c2(0) measured on the samples of different doping levels revealed a high critical field of up to 7.3 T. Pinning potential U ₀, estimated using thermally activated flux-flow (TAFF) model shows that U ₀ is of the order of 10² K. Self-field critical current density (J _c) estimated for the superconducting BDD films showed large J _c ∼ 10⁷ A/cm² due to enhanced flux trapping. (paper)