Analysis of fluctuation conductivity of polycrystalline Er1-xPr xBa2Cu3O7-δsuperconductors

Abstract

In this work we report on conductivity fluctuation measurements in polycrystalline samples of the Er 1−x Pr x Ba 2 Cu3O 7−δ superconductor (x =0.00, 0.05 and 0.10). Samples were prepared by a standard solidstate reaction technique. The results were analyzed in terms of the temperature derivative of the resistivity and of the logarithmic temperature derivative of the conductivity that allowed the identification of power-law divergences of the conductivity. The results show that the transition proceeds in two stages: pairing and coherence transition. Also, our results, from the critical exponent analysis, show a two-peak splitting at pairing transition, indicating possibly a phase separation. On approaching the zero resistance state, our results show a power-law behavior that corresponds to a phase transition from paracoherent to a coherent state of the granular array.

Fluctuation-Induced Conductivity of Polycrystalline (Ho–Ce)Ba 2 Cu 3 O $_{7-\boldsymbol\delta}$ Superconductor

“…We believe that this pairing transition splitting may result from a phase separation arising from a strong structural disorder at microscopic level induced by Ce/Pr doping [22,23]. This behavior has been observed in [20,21], Y 1−x Ce x Ba 2 Cu 3 O 7−δ (polycrystalline) [24], and Er 1−x Pr x Ba 2 Cu 3 O 7−δ (polycrystalline) [25]. The temperature splitting, , between the two dρ/dT peaks can be observed from Fig.…”

Conductivity of single-crystal Y1−yPryBa2Cu3O7−δ over a wide range of temperatures and Pr concentrations

“…[29][30][31] Although many articles have been published regarding the influence of praseodymium on electrical transport in Y 1Ày Pr y Ba 2 Cu 3 O 7Àd compounds, 32 this question is still under intense discussion. To some extent, this is because much of the experimental data have been obtained from film 33 and polycrystalline 34,35 samples with widely different technological prehistories. Research on the normal and fluctuation conductivity in single-crystal Y 1Ày Pr y BaCuO with a high degree of perfection is of great interest, since these very pure materials offer the possibility of varying the scattering parameters and electrical conductivity in a controlled manner by changing the Pr content.…”