Preparation and critical current density of a Bi-based superconducting whisker composite

Abstract

A Bi2Sr2CaCu2Ox (Bi-2212) superconducting whisker composite consisting of Bi-2212 powder and Bi-2212 superconducting whiskers has been prepared. The powder and the whiskers have been prepared separately, mixed at a weight ratio of 1.0/0.05 (powder/whisker), and sintered in air. The ab plane of the whisker tends to be aligned parallel to the pressed plane in the composite. Zero resistivity temperature ( Tc,zero) for the composite is 75 K and critical current density (Jc) is 250 A/cm2 at 71 K under zero magnetic field. This value is about ten times larger than for a sintered sample without the whiskers (Tc,zero = 74 K). The reason for the increase in Jc is that the whiskers act as bypasses for superconducting current.