Authors: W Y Yip R AbdShukor
Publish Date: 2009/05/02
Volume: 22, Issue: 7, Pages: 705-709
Abstract
The TlSr2Ca1−x R x Cu2O7 Tl1212 phase with R = Dy Tb and Ho for x=01–06 has been studied by powder xray diffraction method and electrical resistance measurement All the samples showed a metallic normal state behavior No correlation between ionic radius and T c onset is observed The three series show the highest volume fraction 97 of Tl1212 phase for x=05 The highest T c onset does not correspond to the highest volume fraction The above results are explained as due to the mixed valence state of Dy and Tb in the Tl1212 phase
Keywords: