SPECIFIC-HEAT OF SUPERCONDUCTING HGBA2CA2CU3O8 BETWEEN 65-K AND 200-K

The specific heat C(p)(T) of a polycrystalline sample containing HgBa2 Ca2Cu3O8 (Hg-1223) as the dominant phase has been measured between 65 and 200 K. The C(p)/T data show a distinct anomaly around T(c)=132.5 K . After subtraction of a fitted background, we deduce a value for DELT AC(p)/T(c) of 12-18 mJ/mole K2 for the investigated sample. From the s hape of DELTAC(p)/T, we conclude that fluctuations near T(c) play an i mportant role also in this type of compound. Our measurements unambigu ously confirm that superconductivity below T(c)=132.5 K is a bulk phen omenon in Hg-1223.