Effects of Sr substitution on dimensionality and superconducting properties ofHg0.7Pb0.3Ba<

Abstract

The effects of Sr substitution on the Ba site for Hg 0.7 Pb 0.3 Ba 2 Ca 2 Cu 3 O y superconductors were studied. The irreversibility line for the Sr-substituted compound is much steeper compared to the pristine sample. From the analysis of the reversible magnetization, we found that the fluctuation magnetization is much suppressed in the Sr-substituted compound, though the high-field magnetization data around T c (H) still displayed twodimensional scaling behavior. This feature can be explained by the enhanced interlayer coupling strength associated with the Sr substitution. Various thermodynamic parameters were obtained from the theoretical analysis. It is notable that the zero-temperature upper critical field H c 2 (0) of the Sr-substituted sample is about two times that of the nonsubstituted sample.

Scaling of the Equilibrium Magnetization in the Mixed State of Type-II Superconductors

“…This type of κ(T ) behavior resulted in practically all published analyses, in which the Hao-Clem model was applied to experimental magnetization data. [24][25][26][27][28][29][30][31][32][33][34][35][36] The standard explanation is that because of thermal fluctuations of vortices, which are not accounted for by the model, this approach is inapplicable at higher temperatures. Considering the data presented in Fig.…”

Superconducting Properties of Hg0.8Cu0.15Sb0.05Ba2Ca2Cu3O8+δ Ceramic with Controlling Sintering Conditions

“…Therefore, this compound consists of a mixture of HgBa 2 Ca 1 Cu 2 O 7+δ (1212) and HgBa 2 Ca 2 Cu 3 O 8+δ (1223) phases, because the 1212 phase is thermodynamically more favorable at elevated temperatures than the 1223 phase [1,2]. Chemical substitution could be a very effective pathway to overcome these problems.…”

Measurement of the anisotropy ratios in single crystals

“…It is now well established that MgB 2 has two different superconducting energy gaps: a large gap originating from two-dimensional (2D) s bands and a small gap originating from three-dimensional (3D) p bands [3][4][5]. Thus, any physical properties related to the superconductivity should be influenced by this multigap property, which is quite different from that of the anisotropic one-gap high-temperature superconductors [27][28][29][30][31]. For example, the anisotropy ratio x ab =x c , or l c =l ab , which is constant for a one-gap superconductor, is no longer constant.…”