STUDY OF SUPERCONDUCTING MATERIAL YBa₂Cu₃O_9-δ BY POSITRON ANNIHILATION TECHNIQUE

Characteristics of superconducting and semiconductor materials with the same composition have been studied at room temperature, 94K, and 77K by the positron annihilation technique. The results indicate that the phase transition of electronic structure in the superconducting material takes place in the superconducting state.