Processing and properties of single grain (RE)-Ba-Cu-O bulk superconductors

Recent advances in the processing of bulk, single grain (RE)BCO high temperature superconductors (HTS) fabricated by top seeded melt growth (TSMG) are described, including the refinement of (RE)2BaCuO5 (RE-211) second phase inclusions in the bulk superconducting (RE)Ba2Cu3O7−δ (RE-123) matrix by mechanical milling, the generation of new nano-scale pinning centres based on the Y2Ba4CuMOy phase (2411), where M = [Nb, Ta, Mo, W, Re, Zr, Hf], and the creation of MILD pinning sites by heavy ion irradiation. Details of a practical melt processing technique for the fabrication of light rare earth (LRE) bulk materials in air, in particular, based on the development of a generic seed crystal are described. Record Jc's have been reported for GdBCO and (NEG)BCO, and trapped fields as high as 3 T and 17 T have been achieved in bulk (RE)BCO grains at 77 and 29 K. Techniques employed to characterise bulk materials, such as Hall probe mapping, magnetoscan and EBSD are outlined. Finally, details of emerging applications of single grain (RE)BCO materials in motors and generators, magnetic bearings, flywheels and trapped flux devices are described.