Crystal growth and annealing study of the high-temperature superconductor HgBa2CuO4+δ

Abstract

The flux crystal-growth method is used to grow reasonably sized, single crystals of the cuprate superconductor HgBa2CuO4+δ (Hg1201). One as-grown sample measured had a Tc of about 80 K with a sharp transition (~ 2 K), although signatures of non-uniform doping were observed. Another sample, which was annealed at 300°C at 8 bar of O2 pressure, was successfully overdoped and had a Tc of about 84.5 K, with a transition width of about 2.5 K. This sample also proved to homogenous, with oxygen dopant being evenly distributed. Samples were therefore successfully grown and prepared for future measurements.