Tracking the formation of 2223 BiSrCaCu oxygen compounds by resistivity and susceptibility measurements reaching Tc(0)=115 K

Unsubstituted and lead-antimony substituted 2223 BiSrCaCu Oxygen compounds have been synthesized and compared by resistivity R( T) and susceptibility χ( T) measurements and chemical analysis. The R( T) and χ( T) measurements show that interface effects occur which are reflected in the R( T) characteristics. The chemical analysis of samples with a resistance zero T_c(0)=114 K and a diamagnetic onset at 115 K yields a severe loss of lead from nominally 40 at% down to about 3 at%, whereas the T_c(0)=110 K samples contain up to about 30 at% of lead. It is assumed that for the formation of the 115 K phase lead oxide acts as a catalyst not being incorporated to a considerable amount into the lattice.