Effect of nonsuperconducting secondary inclusions on the magnetization relaxation in melt-processed RBa2Cu3O7-delta (R = Nd and Yb) bulk superconductors at high temperatures - art. no. 064518

We have studied the effect of nonsuperconducting inclusions on the magnetiz ation relaxation in melt-processed RBa2Cu3O7-delta (R=Nd and Yb) bulk super conductor in a high-temperature region (77 less than or equal toT less than or equal to 90 K). It is found that nonsuperconducting inclusions are main ly effective in reducing the normalized relaxation rate S (= -d ln M/d ln t ) at low fields [b(irr)(= mu H-o(a)/B-irr) less than or similar to0.1] and at high fields (b(irr) greater than or similar to 0.4). A suppression in S is observed in an intermediate field region (0.1 less than or similar to b( irr) less than or similar to0.4) for the samples exhibiting secondary peak effect, suggesting a relation between the peak and the suppression.