The paper provides an experimental basis for preparing large grain (Nd0.33Eu0.27Gd0.39)Ba2 Cu3Oy "NEG-123". MgO seeds proved to be efficient in controlling growth orientation when a small quantity of ZnO of around 0.035 wt.% was added to the NEG-123 matrix. A substantial reduction of liquid phase loss was observed for a proper ZnO concentration. A perfect facet line up to the bottom of the sample with c-axis reflection plane was observed after the melt-growth implying high density of the material and practically no liquid loss. The magnetization measurements suggested that the superconducting transition temperatures were not affected up to 0.035 wt.% ZnO addition. Critical current density Jc, measured at 3 T and 77 K (Ha∥c-axis), increased with increasing ZnO content up to 0.035 wt.%, where it reached maximum value of 100 kA/cm2 and decreased thereafter. The scalling analysis of the pinning force density as a function of the reduced field h = Ha/Hirr (Hirr is the irreversibility field) showed a peak at relatively high position as expected for an optimized pinning structure. The present results indicate high potential of ZnO particles for further enhancement of the material performance.
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