Influence of Y_2BaCuO_5 Particles Distribution in Melt-textured Y-Ba-Cu-O Bulk Superconductor on the Superconducting Properties

Single-domain Y-Ba-Cu-O(YBCO) high-temperature superconductor bulk was fabricated by top-seeding melt texture growth process.The distribution of Y_2BaCuO_5(Y211) particles and its effect on the critical current density (J_c) and levitation force of the bulk samples were investigated. Scan electron microscope (SEM) analysis showed that the distribution of the Y211 particles presented an inhomogeneous character throughout the YBCO matrix.The experimental result also showed that the critical current density and levitation force were in inverse proportion to the mean radius of the Y211 particles.The smaller the diameter of the Y211 particles and the more uniform the distribution of the Y211 particles were,the larger the value of J_c and the levitation force were.For the sample of single-domain YBCO bulk with 20mm in diameter,the levitation force could reach 33N (77K,0.55T) and the magnitude of J_c could reach 6.6×10~4A/cm~2.