Possibility of T_c and J_c enhancement in 10% BaSnO₃-doped MPMG-processed YBCO

The effect of 10% BaSnO₃ addition on the microstructure and the magnetic 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 containing 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' inclusions do not seem to be affected by this doping. Moreover, in spite of these difficulties, we could locally show evidence of '211' refinement and the possibility of T_c enhancement. This results in sensible improvement in J_c(B) properties compared to undoped MPMG samples, up to 1.1*10⁵ A cm ^-2 in zero field, at 77 K and 4*10⁴ A cm ^-2 in 1 T.