High resolution Y-89 NMR measurements have been carried our to study the ef
fect of Y substitution in Bi2Sr2Ca1-xYxCu2Oy. A single resonance line was o
bserved for samples with x greater than or equal to 0.5, while an additiona
l line was observed for x < 0.5, possibly arising from Y which occupies the
Sr site. The resonance of the Y on the Ca site shifts diamagnetically upon
increasing the carrier concentration and paramagnetically upon reducing th
e temperature, in dose relation with the variation of T-c in the system. (C
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