Synthesis and transport properties of oxygen controlled melt growth textured(MixedRE)Ba2Cu3Oy (RE = Nd,Sm, Gd, Eu)

Abstract

((RE)0.33Eu0.33Gd0.33)Ba2Cu3Oy bulksuperconductors (RE = Sm, Nd) were textured by the top seeded melt textured growth method in a reducedoxygen atmosphere, so-called oxygen controlled melt growth (OCMG). Largesingle domains of diameter 16 mm were successfully grown. Their microstructureand their magnetic and transport properties were investigated and compared.The resistive transition was found around 88 K, which is not the optimalTc of 95 K that could be obtained on a small re-oxygenated sample cutout from the bulk. Transport measurements were also performed onthese samples at various temperature from 77 to 88 K. In the case ofNd0.33Eu0.33Gd0.33Ba2Cu3Oy (NEG) composition, the angular dependence of the critical current densities along the(a,b) planes as a function of magnetic field was also measured.Transport critical current densities higher than50 000 A cm−2 arereached at 77 K and up to 2 T, corresponding to the nominal critical currents of 90 A injected through sectionsless than 0.25 mm2 reproducibly. This confirms the high quality of the single domain obtained with a wellcontrolled process, evidencing that mixing of rare earth is a very promising composition fortransport and high-field applications.