Critical field behavior of a multiply connected superconductor in a tilted magnetic field

Abstract

We report magnetotransport measurements of the critical field behavior of thin Al films deposited onto multiply connected substrates. The substrates were fabricated via a standard electrochemical process that produced a triangular array of 66 nm diameter holes having a lattice constant of 100 nm. The critical field transition of the Al films was measured near $T_c$ as a function of field orientation relative to the substrate normal. With the field oriented along the normal ($\theta =0$), we observe reentrant superconductivity at a characteristic matching field $H_m=0.22\mathrm{T}$, corresponding to one flux quantum per hole. In tilted fields, the position $H^{\ast }$ of the reentrance feature increases as $\sec (\theta )$, but the resistivity traces are somewhat more complex than those of a continuous superconducting film. We show that when the tilt angle is tuned such that $H^{\ast }$ is of the order of the upper critical field $H_c$, the entire critical region is dominated by the enhanced dissipation associated with a sub-matching perpendicular component of the applied field. At higher tilt angles a local maximum in the critical field is observed when the perpendicular component of the field is equal to the matching field.

6 pages, 6 figures

References in corpus (1)

• Fermi-liquid effects in the gapless state of marginally thin superconducting films

Cited by in corpus (2)

• Angular magnetic-field dependence of vortex matching in pinning lattices fabricated by focused or masked helium ion beam irradiation of superconducting YBa${}_2$Cu${}_3$O${}_{7-\delta }$ thin films
• Angle-dependent Magnetoresistance of an Ordered Bose Glass of Vortices in YBa${}_2$Cu${}_3$O${}_{7-\delta }$ Thin Films with a Periodic Pinning~Lattice