Comparative Transport Studies of '1212' Superconductors

Abstract

HgBa₂CaCu₂O_6+δ (Hg -1212) thin films were fabricated by exchanging the T1 cations in TlBa₂CaCu₂O_7-δ (Tl-1212) thin films with Hg cations, causing a 30-K increase in Tc. To determine how this exchange effects such a Tc increase, the irreversibility lines, temperature dependence of critical current density, and temperature dependence of Hall angle ofHg-1212 and TI-1212 thin films were measured and then compared. The results strongly suggest that the Tc shift is caused by a doubling of charge carrier density.