Introduction of artificial pinning centers to improve J_e properties of REBa₂Cu₃O_y films under magnetic fields-microstructures of impurity nanorods and their growth mechanism-

Microstructures of impurity nanorods as a c-axis correlation pinning centers in REBa₂Cu₃O_y, films (RE: rare earth elements) have been examined by transmission electron microscopy (TEM). On the basis of the microstructure analyses, the possibility of controlling nanorod structures such as diameter and density was discussed. Furthermore, narnorod growth mechanism was discussed in relation with superconducting film growth. As a result, the formation of nanorods was affected by the stress fields generated by differences of crystal length between the superconductors and impurity materials. The various nanorod structures by changing impurity materials or growth conditions could be explained using the segregation coefficient.