Anisotropy of the thermodynamic response along the<i>a</i>and<i>b</i>axes of the 1:2:3 compounds

Abstract

High-resolution specific-heat data as a function of temperature and applied magnetic field have been obtained on an untwinned ${\mathrm{LuBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathit{y}}$ single crystal near its normal-superconducting transition. The magnitude of the specific-heat anomaly has been found to depend on the magnetic-field strength and the orientation of magnetic field relative to all three crystallographic axes. The implications of this anisotropy, specifically along the a and b axes, will be discussed.