COMPARATIVE-STUDY OF MAGNETIC-FIELDS TRAPPED IN YBA2CU3OY AND SMBA2CU3OY SUPERCONDUCTING BULKS

We have measured the trapped field distribution in plates of melt proc essed YBa2Cu3Oy (Y123) and SmBa2Cu3Oy (Sm123) superconductors that hav e different field dependence of the critical current density (J(c)). S m123 materials were fabricated by the oxygen-controlled melt-growth (O CMG) process and exhibited the peak effect. The trapped fields were me asured by scanning a Hall probe on the sample surface. Measurements we re performed after a field of 3.5 T was applied in the field-cooled pr ocess. On the basis of the critical state model, the magnetic field di stribution was calculated taking account of the field dependence of th e critical current density. The calculated values were in good agreeme nt with the measured data. We have also estimated trapped magnetic fie lds for Y123 and Sm123 when the grain size is enlarged, which showed t hat OCMG-processed Sm123 bulk superconductors have greater potential a s trapped field magnets. (C) 1998 Elsevier Science S.A. All rights res erved.