Aging Effect on Electrical Conductivity of Pure and Al-Doped YBa₂Cu₃O_7−δ Single Crystals with a Given Topology of Planar Defects

Figure 2

The temperature dependence 𝜌_𝑎𝑏(𝑇) of the single crystals (a) YBa₂Cu₃O_7−𝛿 and (b) YBa₂Cu_3−𝑦Al_𝑦O_7−𝛿 before and after long aging in ambient air, curves 1 and 2, respectively. The arrows show the mean-field transition temperature 𝑇^∗ to the pseudogap regime. The extrapolated values of 𝜌_𝑎𝑏(0K) are traced by the dashed straight lines. The insets show the superconducting transitions in 𝜌_𝑎𝑏-𝑇 and 𝑑𝜌_𝑎𝑏/𝑑𝑇-𝑇 coordinates for the same samples. The numbering of the curves in the insets corresponds to that in the main panels.

(a)

(b)