The normal state magnetic susceptibility measurements of high quality
Tl2Ba2CuO6+y, single crystals with various oxygen content have shown t
hat the increasing oxygen content, accompanied by the T-c decrease, le
ads to increase in the number of paramagnetic centers. Thus, T-c decre
ase with oxygen doping may be explained by spin-flip processes of elec
tron scaterring on additional paramagnetic centers.