Critical Current Density, Pinning and Nanostructure of MT-YBCO and MgB2-based Materials

The correlations between structural features, critical current density and pinning landscape of YBa
₂
Cu
₃
O
_7-δ
and MgB
₂
-based materials produced in the forms of bulk melt-textured (MT-YBCO) and polycrystalline (MgB
₂
) blocks and wires with excellent superconducting characteristics were revealed. The impurity oxygen distribution, higher borides inclusions and carbon doping are most important for the critical currents and pinning forces in MgB
₂
, while the twin density and the density of Y211 inclusions are relevant in MT-YBCO.