Measurements of the superconducting properties of grain-aligned HgBa2Ca2Cu3O8+δ

We produced the HgBa2Ca2Cu3O8+δ (Hg1223) superconductor in various conditions and characterized this by X-ray diffraction, Auger electron microprobe, AC susceptibility and resistivity measurement. We found that high mercury pressure and high temperature are essential for the formation of the Hg1223 phase. We also measured several physical properties: Raman spectra, thermoelectric power, tunneling, and magnetization. We produced the grain-aligned Hg-1223 superconductor and discovered a large fluctuation effect from the magnetization. The Ginzburg-Landau theory was used to explain the scaling behavior of magnetization at high field limit. At low field limit, the diamagnetic fluctuating susceptibility χc(T) follows the 3D Lawrence-Doniach model near Tc. The vortex fluctuation effect was also observed. From these measurements, we obtained the parameter dHc2/dT, ζab(0), ζc, GL parameter κ, and γ.