Coherent transition induced by Sr doping on the YBa2Cu3O7-δ single crystal magnetoconductivity

27th International Conference on Low Temperature Physics

Lopes, L.F.^1 ; Vieira, V.N.^1 ; Dias, F.T.^1 ; Silva, D.L.^1 ; Jaeckel, S.T.^2 ; Pureur, P.^3 ; Schaf, J.^3

Instituto de Física e Matemática, Universidade Federal de Pelotas, Pelotas, RS

96010-900, Brazil^1

Instituto Federal Farroupilha, Alegrete, RS

97555-000, Brazil^2

Instituto de Física, Universidade Federal Do Rio Grande Do sul, Porto Alegre, RS

91501-970, Brazil^3

关键词: Coherent transition;    Critical temperatures;    Granular superconductors;    Magneto-conductivity;    Superconducting ordering;    Superconducting transitions;    Temperature dependence;    Thermodynamic fluctuations;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/2/022013/pdf
DOI  :  10.1088/1742-6596/568/2/022013

来源: IOP

【 摘 要 】

We have studied by magnetoresistivity measurements The influence of The low Sr chemical doping on The conductivity thermodynamic fluctuation regimes (TFR) of a YBa1.98Sr0.02Cu3O7-δsingle crystal. The low-current and low-frequency resistivity, ρ(T,H) measurements were performed in a PPMS while DC magnetic fields up to 50kOe were simultaneously applied perpendicular to The ab plane of The single crystal and to The measurement current density. The dρ(T,H)/dT data shows that The superconducting transition of The sample occur is two stages that corresponds to The signature of a granular superconductor. At this scenario is possible to define two critical temperature transitions TC(H) and TC0(H) [TC(H) > TC0(H)]. At TC(H) The superconductivity sets in within The grains and at TC0(H) a coherent transition takes place and a long-range superconducting order takes place over The whole sample. Special attention is reserved to The paracoherent region [TC0(H) ≤ T C(H)] of The ρ(T,H) data. The field and The temperature dependence of The paracoherent TFR behavior is characterized by a power law represented by a critical exponent S03. This exponent is an indicative that The coherence transition of The sample belongs to The 3D-XY universality class with relevant disorder that probably is associated to The low Sr doping.