SPECIFIC-HEAT AND MAGNETIC-SUSCEPTIBILITY OF THE HIGH-TC SUPERCONDUCTOR (BI, PB, SB)2SR2CA2CU3O10

The temperature dependence of the specific heat and magnetic susceptibility of single phase (Bi, Pb, Sb)2Sr2Ca2Cu3O10 has been measured. A distinct jump in the specific heat C(T) at the superconducting transition temperature Tc is obtained with a δC at Tc=6.2±0.2 J/mole K and Tc=109 K. This result combined with an estimate of the Sommerfeld constant γ obtained from scaling the temperature independent contribution of the magnetic susceptibility χ(T) is close to the value of δC expected assuming a weak coupling BCS theory. The γ-value obtained from δC=1.43γTc and the temperature independent contribution to χ(T) is ∼40 mJ/mole K2 which indicates that the electrons are highly correlated with a band mass ≈10m0 where m0 is the free electron mass. These γ-values and the effective electron mass are very similar to those previously reported for other high-Tc superconductors, e.g., YBa2Cu3O7. At low temperatures C(T) can be fitted to A/T2+γT+βT3+CE(T) with A=40 mJK/mole, γ{reversed tilde equals}0.0 and β=1.76 mJ/mole K4 and CE(T) representing a small Einstein-like contribution to C(T) with an Einstein temperature of ∼4 3 K. © 1990.