Enhanced magnetic irreversibility characteristics by expansion of blocking block for Sr2Ca2Cu3O8−δ high-Tc superconductor

Abstract

We demonstrate that the irreversibility field characteristics of high-Tc superconductors are not necessarily enhanced by decreasing the thickness of the non-superconducting blocking block between adjacent superconducting blocks. The experimental data are for the high-pressure-synthesized Sr2Ca2Cu3O8−δ (0(Sr)223; Tc = 105 K) phase and for its water-containing derivative phase (H2O)m/2Sr2Ca2Cu3O8−δ (H-m(Sr)223; Tc = 105 K), which spontaneously forms when the 0(Sr)223 phase is exposed to air at 80 °C. Our results clearly show that the insertion of water into the 0(Sr)223 phase expands the blocking block by 3.1 Å along the c-axis but improves the Jc and Hirr properties while keeping the high Tc intact.