Nanoscale Gd2BaCuO5 particles in (Sm0.33Eu0.33Gd0.33)Ba2Cu3Oy and magnetic levitation at 90.2 K

The excellent pinning performance, due to ball milled Gd2BaCuO5 'Gd-211' particles, recently observed in (Nd,Eu,Gd)Ba2Cu3Oy, was tested with (Sm,Eu,Gd)Ba2Cu3Oy 'SEG-123' and (Nd,Sm,Gd)Ba2Cu3Oy 'NSG-123' bulk superconductors grown by an oxygen-controlled-melt-growth process. In both cases the same effect was present. Microstructure analysis of the SEG-123 sample showed that there are two kinds of secondary phase particle: one between 100 and 200 nm and the other less than 50 nm in size. The former nanoparticles were identified as Gd-211 and Gd-rich SEG-211, the latter were either of LRE-Ba2CuZrOy or (LRE,Zr)BaCuOy. In both SEG-123 and NSG-123 the pinning performance at high temperatures was sufficient for levitation at liquid oxygen temperature (90.2 K). (rapid communication)