Microstructure of partially melted filamentary Hg1223 superconductors

摘要

A microstructure of filamentary Hg1223 superconductor by using CaHgO sub(2) for a vaporizing material was studied to improve the grain alignment and the transport J sub(c). A filamentary precursor Ba sub(2)Ca sub(2)Cu sub(3)Re sub(0.2)O sub(x) was fabricated using a solution spinning method and partially melted in an evacuated quartz tube with a pellet of (CaHgO sub(2)) Ba sub(2)CaCu sub(2.8)Re sub(0.2)(CuF sub(2)) sub(0.2)O sub(x). The reacted sample was a single phase of Hg1223 with T sub(c) value of 135 K. Platelike grains were partly aligned along the fiber length by controlling the heating condition. The J sub(c) value of the sample enhanced by using CaHgO sub(2) instead of HgO for the vaporizing material. Although the J sub(c) value rapidly decreased by applying the field less than 0.1 T, the superconductivity at 77 K of the sample maintained in the field up to 8T.