The low temperature specific heat of Bi1.8Pb0.3Sr1.9CuOy has been meas
ured in the temperature range from 1.5 to 8K to investigate whether it
exhibits features of a d-wave superconductivity. In superconducting s
ample, a specific heat anomaly was observed at T-c, while no anomaly w
as observed in non-superconducting sample. The value of the specific h
eat anomaly Delta C/gamma T-c was quite small compared with the BCS va
lue. This is consistent with the theory of d-wave superconductors by S
un and Maki.