Correlation of magnetic and magneto-optical properties with microstructureanalysis in melt-textured (Nd0.33Sm0.33Gd0.33)Ba2Cu3Oy

Magnetic properties of the melt-processed ternary superconductor (Nd0.33Sm0 .33Gd0.33)Ba2Cu3Oy ("NSG") with non-homogeneously distributed NSG-211 parti cles were investigated by means of magnetic and magneto-optical measurement s. Flux distributions obtained by means of magneto-optic imaging after zero field-cooling and field-cooling were analyzed in order to understand the f lux penetration behavior of this compound. The current-carrying length-scal e was determined from the reverse leg of the magnetization hysteresis loops and compared to the actual dimensions of the sample. This was done both on the whole sample and on three individual domains to which the sample was s ubsequently divided. Magnetization hysteresis loops of all samples exhibite d a strongly developed secondary peak in the temperature range 30 K less th an or equal to T less than or equal to 77 K. The critical current and pinni ng force densities derived from these data were normalized to the values at the peak position. J(max) and F-max respectively, and analyzed as a functi on of applied field reduced both to the respective peak field and irreversi bility field. (C) 1999 Published by Elsevier Science B.V. All rights reserv ed.