Excess conductivity and the pseudogap state in Hf-doped YBa2Cu3O7−δ ceramics

Abstract

The electrical conductivity of hafnium (Hf)-doped YBa2Cu3O[Formula: see text] ceramics is investigated. Hf doping has been revealed to lead to an increase of the number of effective scattering centers for the normal charge carriers. In a broad temperature range, the excess conductivity of the investigated samples obeys an exponential temperature dependence, while near [Formula: see text] it is satisfactorily described by the Aslamazov–Larkin model. Meanwhile, Hf doping has been shown to lead to a notable broadening of the temperature range for the manifestation of the pseudogap anomaly in the [Formula: see text]-plane.