2021   01   en   p.40-44 V.M. Aliev, J.A. Rahimov1, V.I. Eminova, G.A. Alieva2,
Analysis of fluctuation conductivity in Y0,5Cd0,5Ba2Cu3O7-δ


The mechanism of the formation of excess conductivity in cuprate HTSCs YBa2Cu3O7-δ and Y0,5Cd0,5Ba2Cu3O7-δ was considered in the framework of the model of local pairs, taking into account the Aslamazov - Larkin theory near Тcmf. The temperature Tcr of the transition from the 2D fluctuation region to the 3D region (the temperature of the 2D-3D crossover) is determined. The values of the coherence length of fluctuation Cooper pairs ξc (0) along the с axis are calculated. It is shown that partial substitution of Y for Cd in the Y-Ba-Cu-O system leads to an increase in ξc(0) by ~ 3.2 times (from 1.1 Ǻ to 3.6 Ǻ), as well as to an expansion as a region of existence pseudogap, and the region of superconducting (SC) fluctuations near Тcmf. The temperature dependence of the pseudogap Δ*(T) and the values of Δ* (Тcmf) were determined, and the temperatures Tm (122.7K) corresponding to the maximum of the temperature dependence of the pseudogap in Y0,5Cd0,5Ba2Cu3O7-δ were estimated. The maximum values of the pseudogap in the Y0,5Cd0,5Ba2Cu3O7-δ sample are 660K.

Keywords: superconductivity, pseudogap (PG), fluctuation conductivity, coherence length, Y0,5Cd0,5Ba2Cu3O7-δ.
PACS: 74.25. Fy, 74.20.Mn, 74.72. ± h, 74.25. ± q, 74.25.Jb

Received: 15.02.2021


     Institute of Physics of the National Academy of Sciences of Azerbaijan, AZ 1143, Baku, H. Javid Ave., 131
1. Azerbaijan Medical University, AZ 1022, Baku, st. Bakikhanov, 23
2. Institute INKhP NAS of Azerbaijan, AZ 1025, Baku, Khojaly ave. 30
E-mail: v_aliev@bk.ru

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