EFFECT OF GAMMA-IRRADIATION ON PURE AND SILVER-DOPED YBCO SUPERCONDUCTOR

Specimens of high-T(c) superconductors, YBCO and (YBCO)1.96 Ag0.04, we re irradiated with gamma-rays up to an integrated dose of 77 MR. Elect rical resistance vs temperature and the X-ray diffraction patterns of the monolayers of the sample powders were obtained before and after th e irradiations. The normal state resistance of the pure and Ag-doped Y BCO specimens gradually increase as the gamma-dose increases. The inte nsities of the X-ray diffraction peaks of the monolayers of the YBCO p owders decrease with gamma-irradiation without significant change of d iffraction angles or peak widths. The zero resistance transition tempe rature of the Ag-doped YBCO specimens decreases by about 0.5% with gam ma-irradiation at 77 MR. These observations indicate that the high-T(c ) superconductor YBCO is quite sensitive to gamma-irradiation but dras tic lattice expansion does not occur up to a gamma-dose of 77 MR.