Magnetic field dependence of the temperature derivative of resistivity: a probe for distinguishing the effects of pseudogap and superconducting fluctuations in cuprates

摘要

We have studied the magnetic field dependence of the temperature derivative of the resistivity, d rho(H, T)/dT, of a number of Y1-xCaxBa2(Cu1-yZny)(3)O7-delta crystalline thin films over a wide range of sample compositions. From the analysis of the temperature derivative data we have been able to distinguish quite clearly between two characteristic temperature scales: (a) the onset of strong superconducting fluctuation temperature, T-scf and (b) the pseudogap temperature, T-PG. Significantly different characteristic features of d rho(H,T)/dT at T-scf and at T-PG imply that T-scf and T-PG have different physical origins. (c) 2007 Elsevier B.V. All rights reserved.