YBCO bulk superconductors doped with gadolinium and samarium

Highlights: •Undoped, Gd and Sm doped YBCO bulk single-grain superconductors were prepared by the optimized TSMG process. •WDX analyses confirmed the additional presence of 0.1 wt.% Sm and 0.25 wt.% Yb in the samples. •The critical temperature increases with increasing dopant concentration. •Peak effect in the field dependences of critical current density at 77 K is observed. -- Abstract: The YBa2Cu3O7−δ (YBCO, Y123) bulk single-grain superconductors doped with GdBa2Cu3Oy (Gd123) or SmBa2Cu3Oz (Sm123) were prepared by the Top-seeded melt-growth process. The growth conditions of the samples were optimized for different dopant concentrations. Wavelength-dispersive spectrometry (WDS) confirmed that prepared samples contain besides dopants also Sm from the seed and Yb from the substrate. The critical temperature, Tc increases with increasing dopant concentration in the studied range. Peak effect in the field dependences of critical current density, Jc(B) at 77 K was observed