Deterioration of Superconductive Character of Y-Ba-Cu Oxides in Time Duration

The electrical resistivity and magnetic susceptibility of a superconductive [1:2:2] and an electron-irradiated [1:1:2] Y–Ba–Cu oxide were examined in time duration for about one year. There was no remarkable change in the superconductive character within a few months. After half a year, however, a deterioration of the superconductive character seemed to be accelerated. In particular, the electron-irradiated [1:1:2] Y–Ba–Cu oxide showed a significant deterioration in the electric and magnetic characters of the superconductivity.