  We demonstrate that the spin dynamics in underdoped Y(1-z)Ca(z)Ba(2)Cu(3)O(y)
for y=~6.0 exhibit qualitatively the same behavior to underdoped
La(2-x)Sr(x)CuO(4) for an equal amount of hole concentration p=z/2=x<0.11.
However,a spin-gap appears as more holes are doped into the CuO(2) plane by
increasing the oxygen concentration to y=~6.5 for a fixed value of Ca
concentration z. Our results also suggest that Ca doping causes disorder
effects that enhance the low frequency spin fluctuations.
