Little-Parks oscillations of ${T}_{c}$ in patterned microstructures of the oxide superconductor ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$: Experimental limits on fractional-statistics-particle theories

Abstract

We report observation of Little-Parks oscillations in arrays with a 4-μ${\mathrm{m}}^2$ plaquette area, fabricated from c^-axis-oriented ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ films. Near the mean-field transition temperature the magnitude of the oscillations implies a zero-temperature coherence length ξ(0)=15±2 Å. For temperatures more than 1 K below the mean-field transition, the magnitude of the oscillations increases dramatically, apparently signaling a crossover to the dynamics of a Josephson-coupled network. Precise experimental limits can be placed on the value of the flux quantum, severely restricting any anomalous value which may be proposed on the basis of fractional-statistics-particle theories.