NOVEL TRANSPORT BEHAVIOR FOUND IN THE DISSIPATIVE REGIME OF SUPERCONDUCTORS

As the transport current density J in a superconductor is increased beyond its critical value J(c), dissipation sets in resulting in a finite resistivity. The superconducting state itself, however, persists up to the pair-breaking value J(d), where the kinetic energy associated with the current overcomes the condensation energy. Within this dissipative regime between J(c) and J(d), the transport behavior displays a series of interesting physical phenomena (free flux flow, pair-breaking effect, etc.) as the Lorentz force and kinetic energy associated with the current sequentially overcome various intrinsic (e.g., pair-condensation and interlayer-coupling) and extrinsic (e.g., flux pinning) interactions relevant to the superconducting state. This review discusses these phenomena in the context of recent experiments where the existence of these effects was demonstrated in high-T-c, superconductors for the first time. Also described are the general principles of the pulsed-current technique used to extend transport measurements to the required high current densities and power-dissipation levels.