Flux pinning at high magnetic field in melt-processedSmBa2Cu3O7 with nanocrystalline Sm211/Nd422 additives

Abstract

Nano-sized Sm2BaCuO5 (‘Sm211’) and Nd4Ba2Cu2O10 (‘Nd422’) non-superconducting particles were prepared by a typical sol–gel process ofmixing poly-acrylic acid (PAA) with metal ion solutions. Small amounts (1 to1 × 10−2 wt%) of nano-sized Sm211 and Nd422 powders were mixed homogeneously with the precursors ofSm123+25 wt% Sm211 followed by the melt-texture processing in air. It is observed that superconductingproperties of SmBCO with nano-Sm211 or nano-Nd422 additives were greatly enhancedand a clear secondary peak effect was observed. The scale rule analysis shows that theδTc pinning mechanism may be responsible for theJc enhancement at high field. A systematic study of the relationship ofJc(H,T) with different amounts of nm-Sm211 and/or Nd422 additions was performed to determinethe optimum nano-particle doping contents and their pinning mechanisms respectively.