2020   01   en   p.17-20 V.M. Aliev1, J.A. Ragimov2, R.I. Selim-Zade1, B.A. Tairov1,
Analysis of fluctuation conductivity in Y0,6Cd0,4Ba2Cu3O7-δ		  pdf 

ABSTRACT

The mechanism of formation of excess conductivity in cuprate high-temperature superconductors (HTSC) Y0,6Cd0,4Ba2Cu3O7-δ and YBa2Cu3O7-δ was considered within the framework of the local pair model taking into account the Aslamazov-Larkin theory near Tc. The temperature T0 of the transition from the 2D fluctuation region to the 3D region (the temperature of the 2D-3D crossover) is determined. The coherence lengths of the fluctuation Cooper pairs ξc (0) along the c axis are calculated. It was shown that a partial substitution of Y by Cd in the Y – Ba – Cu – O system leads to a decrease in ξc (0) by ~ 2 times (from 6.32 Ǻ to 3.18 Ǻ), as well as to the expansion as the region of existence pseudogaps and superconducting (SC) fluctuations near Tc. The temperature dependence of the pseudogap Δ * (T) and the values of Δ * (Tc) are determined, and temperatures Tm corresponding to the maximum temperature dependence of the pseudogap in these materials are estimated. The maximum values of the pseudogap in samples Y0,6Cd0,4Ba2Cu3O7-δ and YBa2Cu3O7-δ are 34.56 meV and 28.4 meV correspondingly.

Keywords: superconductivity, pseudogap, excess conductivity, coherence length, composition.
PACS: 74.25. Fy, 74.20.Mn, 74.72. ± h, 74.25. ± q, 74.25.Jb

Received: 03.02.2020

AUTHORS & AFFILIATIONS

1. Institute of Physics of the National Academy of Sciences of Azerbaijan, 131, H. Javid Ave., Baku, AZ 1143
2. Azerbaijan Medical University, 23, Bakykhanov str., Baku, AZ 1022
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