Electrical properties of the Y-Ba-Cu-O ceramic superconductors after filling oxygen vacancies with cadmium

An attempt was made to partially substitute Cd for oxygen in Y--Ba--Cu--O superconductors, and to investigate the electrical and superconducting properties of the Y sub 1 Ba sub 2 Cu sub 3 Cd sub x O sub y system. For x < = 0.2, it was found that Cd fills the oxygen vacancies. For x > 0.2, there is a small amount of excess CdO which is responsible for the metal-insulator transition. Substitution of Cd slightly affects the transition temperature (T sub c ), and for x = 0.5, the resistivity of the material drops by at least two orders of magnitude, compared with the undoped 1-2-3 ceramic superconductors. More systematic research must be carried out in samples with x < 0.1 in order to find the best concentration of Cd for higher T sub c and lower electrical resistivity. Graphs. 13 ref.--J.H.