Superconducting properties of high-Tc Bi1.6Pb0.4Ca2Sr2Cu3Oy superconductor

We present measurements of the X-ray diffraction pattern, the electrical resistivyt, and the magnetization M(T,H) of the Bi1.6Pb0.4Ca2Sr2Cu3Oy superconductor with Tc=107 K. The upper critical field Hc2 is obtained from magnetization measurements. The magnetization M(T) is linearly increased with temperature in a range of about 15 K below Tc. From the slope dHc2/dT near Tc, the zero-temperature upper critical field Hc2(0) of 84 T is estimated. Also, the lower critical field Hc1(0) is obtained 112 Oe from the deviation of the magnetization curve. We estimate the fundamental superconducting parameters: the coherence length ξ=20 A, the penetration depth λ0=2700 A, the Ginzburg-Landau parameter κ=136, and the jump in the specific heat ΔC/Tc≅2.7 mJ/mol K2. (orig.)