We have fabricated melt-textured Ho-Ba-Cu-O bulk superconductors with a composition of HoBa2Cu3Oy(Ho123)+0.4Ho2BaCuO5(Ho211) in air. Several kinds of precursor compounds having Ho211 starting powders with different sizes are prepared by calcinining Ho2O3, BaO2 and CuO at 1173∼1273 K. The diameter of Ho211 secondary particles dispersed in the Ho123 phase is reduced with decreasing the particle size of the Ho211 starting powder, resulting in the improvement in Jc properties. The maximum Jc value is 7.2×108 A/m2 at 77 K in self-field. The Ag added large single-domain bulk of 32 mm in diameter is also fabricated. The trapped-field of 1.2 T has been achieved at 77 K for this bulk sample.
