The in-plane conductivity of YBa2Cu3–yAlyO7–x single crystals with a defined topology of planar defects has been investigated. It is shown that Al impurities act as effective scattering centers for normal-state carriers. The excess conductivity of the studied samples over a wide temperature range follows an exponential temperature dependence, while near Tc it is satisfactorily described by the Aslamazov–Larkin theoretical model. Partial substitution of Cu with Al leads to a significant expansion of the temperature interval in which the pseudogap anomaly exists in the ab plane. The fractal analysis of the “tweed” structures has been performed.
Lazorenko et al. (Wed,) studied this question.