NONDESTRUCTIVE ANALYSIS AND CONTROL OF DOPING RATE IN LA-2-X(BI,SR)(X)CUO4+ -Y/

Systematic heat treatments of single crystals of La2-xBixCuO4+y (x = 0 .05) and La2-xSrxCuO4-y (x = 0.15) combined with accurate measurements of the sample weight demonstrated that the doping rate can be control led and determined without decomposing the sample. For the former, the absolute doping rate 2y was determined in the region of 0 less than o r equal to 2y less than or equal to 0.020 and the detailed doping depe ndence of the Neel temperature was obtained. For the latter, the effec tive doping x(eff) = x - 2y can be reduced continuously from 0.15 to a round 0.07 by deoxygenation. It is confirmed that the superconductivit y was destroyed at x(eff) approximate to 0.10 irrespective of the deta ils of the heat treatments.