Magnetic Properties of High-Tc Bi1.4Pb0.6Ca2Sr2Cu3Oy Superconductor

Abstract

Magnetization measurements were performed on Bi1.4Pb0.6Ca2Sr2Cu3Oy superconductor with Tc=108 K using a vibrating sample magnetometer in fields up to 18 kOe. The magnetization M(T) is linearly increased in a temperature range of about 15 K below Tc, and the temperature dependence of Hc2 is obtained from the onset of diamagnetism. From the upper critical field slope ∂Hc2/∂T, the zero-temperature upper critical field Hc2(0) is estimated about 61 T. Also, the lower critical field Hc1(0) is 111 Oe using the magnetization measurement M(H). From the magnetic critical fields Hc2 and Hc1, we estimate the superconducting parameters: the coherence length ζ0=23 Å, the penetration depth λ0=2600 Å, the Ginzburg-Landau parameter κ=113 and the jump in the specific heat ΔC/Tc≃2 mJ/molK2.