Infiltration growth processing of single grain (Gd,Dy)BCO bulk superconductors: Optimization of liquid phase mass and characterization of physical properties

Abstract

Infiltration of an optimal amount of liquid (Ba3Cu5O8 denoted further as “035”) for efficient peritectic growth is a primary requirement in the infiltration growth (IG) processing of high-quality REBa2Cu3O7-δ products. Recently, we optimized the Dy content and the time-temperature schedules for top-seeded IG processing of (Gd,Dy)Ba2Cu3O7–δ [(Gd,Dy)BCO] single grain superconductors. Aiming to fabricate larger sized (Gd,Dy)BCO (80 wt. % Gd2BaCuO5 and 20 wt. % of Dy2BaCuO5) single grain bulk superconductors, different liquid phase [LP = ErBa2Cu3O7–δ (Er-123) and mixed with 035] sources were employed and the LP content was optimized by varying its mass. The increase in Er-123+035 mass assured an abundant amount of liquids for peritectic reaction. The Er-123+035 ratio of 1:1.4 was found to be optimum. The optimized liquid phase infiltration enabled an effective control of (Gd,Dy)2BaCuO5 (211) secondary phase size and content in final microstructures. Bulk single-grain (Gd,Dy)BCO superconductors were fabricated by the top-seeded IG process with an LP mass of 1 and 1.4 wt. %. A fully grown single grain bulk (Gd,Dy)BCO superconductor was attained. The sufficient LP infiltration resulted in a greatly improved critical current and trapped field performance. Scaling of bulk volume flux pinning force was studied with the aim of identifying flux pinning mechanisms effectively occurring in the material.