SPECIFIC HEAT OF THE HIGH Tc SUPERCONDUCTOR Bi-Sr-Ca-Cu-O

The Bi-Sr-Ca-Cu-O superconductor with the nominal composition (1113) were prepared. An orthorhombic unit cell (a=0.544nm, b=0.543nm, c=3.07nm) was determined by X-ray diffraction. The resistance transition curve shows that the sample has an onset around 110K and the zero resistance temperature at 85K. The mutual inductance measurement also shows a two-step transition which correspond to two superconducting phases as well as that in the resistive transition. The specific heat measurement was performed in the range of 56K to 130K by continuous scanning method. A simple extrapolation of the curve was made both from below and above Tc to yield ΔC=45 mj/g.K and ΔC/Tc=0.49 mj/g.K2. From these values, the Sommerfeld constant γ and the Debye temperature θD were estimated.