Effect of Long Aging on the Resistivity Properties of Optimally Doped <inline-formula> <tex-math notation="TeX">$\hbox{YBa}_{2}\hbox{Cu}_{3}\hbox{O}_{7-\delta}$</tex-math></inline-formula> Single Crystals

Abstract

We investigate conducting properties in the basal abplane before and after a long time exposure in air atmosphere of optimally oxygen doped YBa 2 Cu 3 O 7−δ single crystals. Prolonged exposure leads to an increase of the effective scattering centers of the normal carriers. The excess conductivity in a wide temperature range has exponential temperature dependence and near the critical temperature is well described within the Aslamazov-Larkin theoretical model. The prolonged exposure increases to a great extent the temperature range of the implementation of the pseudogap state, narrowing the linear section of the temperature dependence of the resistivity in the ab-plane, ρ ab (T).