Subgrain structures and their effects on critical current properties in large single-domain RE123 bulk superconductors.

We have studied the microstructures of subgrains in large single-domain RE123 (RE=Y, Sm) bulk superconductors through microscopic observation and X-ray pole figure analyses. We have found that misorientation of the subgrains increases along with the crystal growth, and also that the misorientation has positive relation to the size and concentration of the second-phase particles. Such subgrains are considered to affect current carrying capabilities in bulk materials, so that we performed magnetic and electric measurements for several samples having different subgrain structures. The relationships between obtained <f>Jc–B</f> or AC transport characteristics and subgrain geometries are discussed. [ABSTRACT FROM AUTHOR]