Improvements of liquid source for infiltration and growth of GdBa2Cu3O7−x superconducting single grains

► New Gd-based liquid sources were used to fabricate GdBa2Cu3O7-x single grains. ► The infiltration and growth technique is much simplified. Also a new Y-based liquid source was first applied for fabrication of GdBa2Cu3O7-x. ► Employment of Y-based liquid source is more efficient and economical.