Abstract
High Tc superconducting materials of the Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O systems usually consist of many phases which are about few micron meters in size and are different from each other in composition. Analysis of many phases with EPMA confirmed that the superconducting phase is Y1Ba2Cu3O7−δ.
Valence states of the Cu-O bond depend on superconducting states. It was made clear that the shapes and energies of O-Kα peaks largely depend on the types of crystal structures. This result indicated that the superconducting phase and the incomplete reaction phase are the perovskite and another crystal type, respectively. Moreover, the Cu valence of the Y-Ba-Cu-O superconductive phase was estimated to be +2.4 from the measured peak ratio Cu-Lβ/Lα related to Cu Valences.
