TRANSPORT CRITICAL-CURRENT AND VOLTAGE-CURRENT CHARACTERISTICS OF BI (2223) SILVER-CLAMPED THICK-FILMS

The transport critical current properties of Bi (2223) silver-clamped thick films are studied by the measurement of its dependence on magnet ic field and temperature close to T(c). It is found that the transport critical current follows a power law J(c) approximately (1 - T/T(c))3 /2 for the sample with J(c) > 2.0 x 10(4) A/cm2 (77 K, zero field) and that J(c)(II) is basically reversible for increasing and decreasing m agnetic field. After the transport current exceeds the critical curren t, the voltage-current (V-I) characteristics show a flux-creep-like be haviour until they smoothly join the flux-flow state. From the measure ment of V-I curves, the pinning property of the sample may be estimate d using the flux-creep mode. The flux-flow resistance is found to have a nonlinear magnetic field dependence.