5,310 research outputs found
Focused-ion-beam-induced deposition of superconducting nanowires
Superconducting nanowires, with a critical temperature of 5.2 K, have been
synthesized using an ion-beam-induced deposition, with a Gallium focused ion
beam and Tungsten Carboxyl, W(CO)6, as precursor. The films are amorphous, with
atomic concentrations of about 40, 40, and 20 % for W, C, and Ga, respectively.
Zero Kelvin values of the upper critical field and coherence length of 9.5 T
and 5.9 nm, respectively, are deduced from the resistivity data at different
applied magnetic fields. The critical current density is Jc= 1.5 10^5 A/cm2 at
3 K. This technique can be used as a template-free fabrication method for
superconducting devices.Comment: Accepted for publication in Applied Physics Letter
A New Phenomenology for the Disordered Mixed Phase
A universal phase diagram for type-II superconductors with weak point pinning
disorder is proposed. In this phase diagram, two thermodynamic phase
transitions generically separate a ``Bragg glass'' from the disordered liquid.
Translational correlations in the intervening ``multi-domain glass'' phase are
argued to exhibit a significant degree of short-range order. This phase diagram
differs significantly from the currently accepted one but provides a more
accurate description of experimental data on high and low-T materials,
simulations and current theoretical understanding.Comment: 15 pages including 2 postscript figures, minor changes in published
versio
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