Studies into the phase transformation of Bi-2223 precursor powders using X-ray diffraction and SQUID susceptibility measurements

An optimized processing route for formation of the Bi-2223 phase, from a highly reactive precursor powder, is of obvious importance in achieving a high J/sub c/ in powder-in-tube (PIT) tapes, Here, we report the dependence of the SQUID susceptibility signal on the phase content and heat-treatment of the Bi-2223 precursor powders. Magnetic susceptibilities as measured by SQUID reveal differences in the powder quality not seen by x-ray powder diffraction. In particular, Bi-2223 detection is enhanced using SQUID. The rate of phase transformation to the 2223 phase in various precursor powders exhibiting significantly different SQUID signals will be discussed.