POSSIBILITY OF T(C) AND J(C) ENHANCEMENT IN 10-PERCENT BASNO(3)-DOPEDMPMG-PROCESSED YBCO

The effect of 10% BaSnO3 addition on the microstructure and the magnet ic properties of MPMG-processed samples has been investigated. At high temperature, BaSnO3 was found to react rapidly with the liquid phases to form inclusions, a few micrometres in size, of a new phase contain ing Y, Ba, Cu, Sn, Pt, O components. It is difficult to homogeneously distribute these new phase inclusions in the microstructure, but the ' 123' grain size, the stoichiometry and the distribution of '211' inclu sions do not seem to be affected by this doping. Moreover, in spite of these difficulties, we could locally show evidence of '211' refinemen t and the possibility of T(c) enhancement. This results in sensible im provement in J(c)(B) properties compared to undoped MPMG samples, up t o 1.1 X 10(5) A CM-2 in zero field, at 77 K and 4 x 10(4) A CM-2 in 1 T.