The effect of oxygen partial pressure on melt growth processing for filamentary Dy-Ba-Cu-O Superconductors

Precursor filaments of Dy-Ba-Cu-O super-conductor were prepared by a solution spinning method and partially melting in an atmosphere gas with various oxygen concentrations. It was found that the transport Jc value at 77 K and 0 T of the filamentary sample was strongly dependent on the partial-melting temperature and gas atmosphere. The samples partially melted under flowing 1%O₂+Ar gas exhibited Jc values larger than 10⁴ A/cm² over a wide temperature range of 980-1040°C and a dense microstructure. The filamentary sample with the starting composition of Dy:Ba:Cu=1.18:2.12:3.09 treated at 1020°C under flowing 1%O₂+Ar showed a transport Jc value greater than 4.3×10⁴ A/cm² at 77 K and 0 T, and the Jc value of 2.0×10³ A/cm² was maintained up to the magnetic fields of 14 T. The samples partially melted in 20%O₂+Ar gas and 100%O₂ gas showed relatively low Jc value of 6.0×10³ A/cm² and 1.2×10² A/cm² at most.