Influence of the pseudogap on the Nernst coefficient of Y_0.9 Ca_0.1Ba₂Cu₃O_y

¹  Cavendish Laboratory, Department of Physics, University of Cambridge J. J. Thomson Avenue, Cambridge CB3 0HE, UK, EU
²  Institute of Low Temperature and Structure Research, Polish Academy of Sciences P.O. Box 1410, 50-950 Wrocław, Poland, EU
³  Department of Physics, University of Rajshahi - Raj-6205, Bangladesh
⁴  Department of Physics, Faculty of Science, University of Zagreb - P.O. Box 331, Zagreb, Croatia

Corresponding author: m.matusiak@int.pan.wroc.pl

Received: 23 December 2008
Accepted: 15 March 2009

Abstract

We have studied the Nernst coefficient, , of epitaxial thin films of the superconductor YCa_xBa₂Cu₃O_y with and . The sample has been measured at three different values of y, in the over- (OV), optimally- (OP), and under-doped (UD) states. As the doping level is reduced, starts to fall linearly with T at the temperature (T^*) where we expect to see the influence of the pseudogap. The onset temperature of the superconducting fluctuation contribution to was found to vary slowly with the hole concentration (p) between and 0.197. For the OP and UD samples, is unusually large, being comparable with where S is the Seebeck coefficient and the Hall angle.