Enhancement of Peak Effect in <scp> <scp>Y</scp> </scp> – <scp> <scp>Ba</scp> </scp> – <scp> <scp>Cu</scp> </scp> – <scp> <scp>O</scp> </scp> Bulk Materials by the Addition of Nano‐Sized <scp> <scp>Sm</scp> </scp> ₂ <scp> <scp>O</scp> </scp> ₃

Abstract

Recently, the significant peak effect was observed in the CeO 2 doped Y – Ba – Cu – O ( YBCO ) bulk materials grown using the infiltration growth ( IG ) method. The peak effect was attributed to the compositional fluctuations in the matrix, ( Y , Sm ) BCO . However, it was found that the peak effect was strongly spatially dependent. The inductively coupled plasma mass spectrometry (ICP ‐ MS ) results show that the concentration of Sm ranges from 5.8 × 10 −2 to 7.0 × 10 −3 wt% within the bulk. Notably, the peak effect is only observed in specimens where the concentration of Sm is higher than 1.5 × 10 −2 wt%. The spatial distribution of Sm dissolved from the SmBCO seed is the result of the way in which the liquid ( BaCuO 2 and CuO ) flows during the melting process of the IG technique. To suppress the variation in the composition, nano‐sized Sm 2 O 3 particles are added to the precursor powders in this study. Microstructural analysis demonstrates that with the addition of nano‐sized Sm 2 O 3 , the concentration of Sm can be enhanced to be higher than 1.5 × 10 −2 wt% within the bulk. Therefore, the peak effect can be observed throughout the bulk material. Besides, more symmetrical trapped magnetic field profiles can be obtained.