Three-dimensional superconducting behavior and thermodynamic parameters of HgBa2Ca0.86Sr0.14Cu2O6δ

Abstract
This study measures the temperature dependence of reversible magnetization of grain-aligned HgBa2Ca0.86Sr0.14Cu2O6δ high-Tc superconductor with external magnetic fields parallel to the c axis. The magnetization is field independent at T*=114.5 K, which indicates strong thermal vortex fluctuations. From the vortex fluctuation model, the lower limit of coherence length along the c axis ξc(0)2 and the anisotropy ratio γ<~7.7 has been obtained, which implies that this sample is anisotropic three-dimensional (3D) superconductor as Y1Ba2Cu3O7δ. These results are supported by good 3D scaling behavior of high-field magnetization around Tc(H) as a function of [TTc(H)](TH)23. The thermodynamic critical field Hc(T) and the Ginzburg-Landau parameter κ=114.8 were extracted from the model of Hao et al. Also, the various thermodynamic parameters were obtained: the penetration depth λab(0)=1913 Å, coherence length ξab(0)=13.9 Å, and the zero temperature upper critical field Hc2(0)=170.4 T.