AC and DC electrical resistivity measurements in Ba₂HoCu₃O_7-δcompounds

Abstract

Detailed AC and DC electrical resistivity measurements in Ba2HoCu3O7- delta samples are reported. Although all samples have a very similar transition temperature to the superconductor state (about 92 K), their normal resistivity shows in some cases important differences. In the whole frequency range examined (up to 2 kHz), their AC resistivity is frequency independent and qualitatively similar to the DC resistivity. The behaviour of resistivity around Tc seems not be affected by the presence of the magnetic holmium ions. The excess conductivity above Tc strongly depends on the properties of the samples in the normal state.