Growth and physical properties of melt textured (Gd,Y)Ba2Cu3Ox

Abstract Melt textured samples grown from mixtures of GdBa 2 Cu 3 O x with Y 2 BaCuO x , and from GdBa 2 Cu 3 O x with Gd 2 BaCuO x , were successfully grown in air using the top seeding method employing NdBa 2 Cu 3 O x seed crystals. For GdBa 2 Cu 3 O x /Y 2 BaCuO x , the superconducting transition temperature is 91 K (diamagnetic onset) and the critical current at 77 K is 25 000 A/cm 2 at zero applied field and above 10 000 A/cm 2 at 2 T. The irreversibility field at 77 K is about 6 T. The green phase particles are small and well dispersed, even without the addition of Pt. However, samples grown in air from the GdBa 2 Cu 3 O x /Gd 2 BaCuO x mix had T c 's of 75–80 K, fairly low critical currents and showed large green phase inclusions.