engleski

Influence of the pseudogap on the Nernst coefficient of Y(0.9)Ca(0.1)Ba(2)Cu(3)O(y)

We have studied the Nernst coefficient,  (T), of epitaxial thin films of the superconductor Y1-xCaxBa2Cu3Oy with x =0.05 and x = 0.1. The x = 0.1 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,  (T) 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  (T) was found to vary slowly with the hole concentration (p) between p = 0.118 and 0.197. For the OP and UD samples,  (T>T*) is unusually large, being comparable with |S tan | where S is the Seebeck coefficient and  the Hall angle.

Nernst effect; Pseudogap; Superconducting fluctuation

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