INFLUENCE OF HOLE FILLING BY CO AND HOLE DOPING BY CA ON THE SUPERCONDUCTIVITY OF ERBA2CU3O7-DELTA

The structural and superconducting properties of (Er1-yCay)Ba-2 (Cu1-x COx)(3)O-z samples are investigated using X-ray diffraction, resistivi ty and oxygen content measurements. The effect of increasing Co concen tration in ErBa2(Cu1-xCox)(3)O-z lowers the carrier concentration and decreases T-c, which is attributed to hole filling by Co. This suppres sion of T-c has been compensated by appropriate hole doping with Ca, f or instance, in the oxide (Er1-yCay)Ba-2(Cu0.94Co0.06)(3)O-z, the T-c increase from 34 K (y = 0.0) to 85 K (y = 0.18, compensated oxide) as the hole filing by Co is completely balanced by hole doping from Ca. C opyright (C) 1996 Elsevier Science Ltd