Levitation force and trapped magnetic field of top-seeded melt growth processed YBCO superconductors

종자결정성장법으로 제조한 YBCO 초전도체의 자기 부상력과 포획자력 특성

YBCO superconductors were prepared by top-seeded melt growth process using various numbers of seeds. The levitation forces and trapped magnetic fields of the top surfaces of the samples were measured using Nd-B-Fe permanent magnets It was found that the processing time was greatly reduced by multiple seeding, but the properties were decreased as the number of seeds was increased. The degradation of the properties is attributed to the presence of the nonsuperconducting phases at the grain boundaries as result of the entrapment of a residual melt at grain boundaries during melt processing.