We report oscillatory magnetoresistance in various superconducting films, with a magnetic-field period ∆B ∼ 0.1 T that is essentially independent of sample dimensions, temperature, transport current, and the magnitude and orientation of the magnetic field, including magnetic fields oriented parallel to the film plane. The characteristics of these oscillations seem hard to reconcile with previously established mechanisms for oscillations in magnetoresistance, suggesting the possibility of a new type of physical origin.

The electrical transport properties of c-axis oriented Nd 1.85 Ce 0.15 CuO 4 − δ superconducting films have been investigated to analyze the pinning mechanism in this material. The samples were grown on SrTiO 3 substrates using the dc sputtering high-pressure technique, whereas a detailed analysis of the structure and local composition of the films has been achieved using highresolution electron microscopy and x-ray microanalysis. Magneto-resistance and current-voltage measurements, in the temperature range from 1.6 to 300 K and in magnetic field up to 9 T, have been reported. In particular, the anisotropic coefficient defined as the ratio between the parallel upper critical field, ∥ H c2 ab, and the perpendicular one, ∥ H c2 c, has been evaluated, pointing out the high anisotropy of this compound. Furthermore, the vortex activation energy as a function of the applied magnetic field, parallel and perpendicular to the CuO 2 planes, has been derived and compared with the flux-pinning forces to enlighten the peculiar nature of pinning centers in this material.

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We investigated current induced depairing in the Bi2Te3/FeTe topological insulator-chalcogenide interface superconductor. The measured depairing current density provides information on the magnetic penetration depth and superfluid density, which in turn shed light on the nature of the normal state that underlies the interfacial superconductivity.

We investigated the dissipative regime of the Bi 2 Te 3 /FeTe topological insulatorchalcogenide interface superconductor at temperatures well below the Berezinski-Kosterlitz-Thouless transition. We observe a transition in the current-resistance and temperature-resistance curves that quantitatively agrees with the Likharev vortex-explosion phenomenon. In the limit of low temperatures and high current densities, we were able to demonstrate the regime of complete vortex-antivortex dissociation arising from current driven vortex-antivortex pair breaking.