Fine Structure in a High-Resolution Vortex Dissipation Study of YBa2 Cu3O7- delta.

Abstract

Using high- $Q$ double-torsional silicon oscillators vibrating at extremely low amplitude, numerous fine minima and maxima have been observed in the dissipation vs temperature data for certain characteristic fields perpendicular to the $c$ axis in single crystal ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$. These features are mirrored in the frequency shift vs temperature data. An intrinsic pinning model in which the dissipation minima correspond to conditions of commensureability between the interlayer spacing and both the coherence length and Abrikosov lattice spacing is suggested to explain these features.