High pressure synthesis and properties of HgBa2Ca4Cu5Oy (Hg-1245) superconductor

Abstract

We have synthesized an almost single phase sample of HgBa2Ca4Cu5O y with T c of 108K using a high pressure and high temperature technique. The carreier concentration, N H, was deduced from the Hall coefficient R H using a simple relation (N H=1/(eR H)) at 300 K and the Hall number per CuO2 plane was estimated to be 0.12 for this sample. We also observed a T 2 dependence of the Hall angle (cot θH). The critical current density (J c) and irreversible field (Birr) have been estimated from measurements of magnetic hysteresis loops assuming Bean's critical state model. The Birr for this sample as a function of temperature was lower than HgBa2Ca2Cu3O y (Hg-1223). This result suggests that the anisotropy in Hg-1245 is seem to be larger than that in Hg-1223 and inter-layer coupling among five CuO2 planes in Hg-1245 becomes weaker than that in Hg-1223 by adding two CuO2 planes.