Characteristics of the low-temperature conductivity of a superconducting ceramic BaPb/sub 1-x/Bi/sub x/O/sub 3/ associated with its granular structure

Journal Article · Tue May 01 00:00:00 EDT 1984 · Sov. Phys. - Solid State (Engl. Transl.); (United States)

OSTI ID:6323556

Zaitsev-Zotov, S V; Protasov, E A

An investigation was made of the conductivity of ceramic BaPb/sub 1-x/Bi/sub x/O/sub 3/ samples below the critical temperature. The low-temperature conductivity anomalies reported earlier by the present authors and others were associated with their granular structure. The current-voltage characteristics recorded after a resistive superconducting transition as a result of heat treatment in vacuum were of the usual shape expected for one-particle tunneling. This made it possible to attribute the anomalies of the low-temperature conductivity of such samples observed earlier (such as the appearance of an activation-type growth of the resistivity at T<10 K with an activation energy dependent on the magnetic field) to one-particle tunneling across grain boundaries. Superconducting samples characterized by an anomalous behavior of the conductivity in the mixed state (hysteresis and two maxima in the dependence of the resistivity on the magnetic field) exhibited current-voltage characteristics typical of granular systems with the Josephson coupling between the grains, so that the observed anomalies could be attributed to the Josephson and one-particle tunneling across grain boundaries. The resistivity maximum in a field of H = 0.2 kOe (at T = 4.2 K) was due to a redistribution of the magnetic field in a sample on transition to the mixed state. When the conductivity in the normal state of a ceramic sample was high, an anomalous behavior of the conductivity was observed at high values of the transport current.

• Research Organization: Engineering-Physics Institute, Moscow
• OSTI ID: 6323556
• Journal Information: Sov. Phys. - Solid State (Engl. Transl.); (United States), Vol. 26:5
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
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