Angular field dependence of the Nernst effect in Bi 2Sr 2CaCu 2O 8+ δ

Abstract

The anomalous Nernst effect in hole-doped cuprates has been interpreted in terms of the existence of a superconducting order parameter well above the transition temperature, T c( H). In order to improve the understanding of this problem, we have measured the angular field dependence of the Nernst signal in Bi 2Sr 2CaCu 2O 8+ δ single crystals. The experiment was done tilting the magnetic field with respect to the direction of the temperature gradient, above and below T c( H), with applied fields up to 16 T. We have found that all the curves are scaled on one curve against the reduced field H cos θ at a fixed temperature.