Magnetic Properties of Improved Molar Ratio Y_1.6Ba_2.3Cu_3.3O_7-y Bulk Magnet

YBCO bulk superconductor was fabricated by the seed crystal growth method using a Sm 1.8 Ba 2 Cu 3 O 7-y (Sm123) seed. The molar ratio of Y was increased in order to increase the flux pinning magnetic force. The density of Y211 phase, playing the role of flux pinning center for superconducting bulk magnetic force, was observed to increase in the microstructure of Y 1.6 Ba 2.3 Cu 3.3 O 7-y specimens, as the composition of Y, constituting the superconducting bulk, increased. The measured superconducting critical current density of Y 1.6 Ba 2.3 Cu 3.3 O 7-y superconducting bulk was 36,247 A/cm 2 , a 17% increase due to the increase of Y composition. The measured magnetic levitation force was 74 N, and the maximum trapped magnetic force was 2.56 kG. The superconducting magnetic force tended to increase as the Y composition in the bulk increased. The method of controlling the molar ratio of the elements constituting the superconductor bulk in this study seems to be an alternative to increase the magnetic force of superconducting bulk.