Variation of leakage current conduction mechanism by heat treatment in Bi-based lead-free piezoelectric ceramics

The leakage current mechanism in the as-sintered and quenched 0.75BiFeO(3)-0.25BaTiO(3) (0.75BF-0.25BT) ceramics is evaluated by the space-charge-limited current (SCLC), Poole-Frenkel (P-F) emission, Schottky (ST) emission, and Fowler-Nordheim (F-N) tunneling mechanism. The discrepancy observed in the optical dielectric constant of BF and BT between the reported value and the values calculated from the P-F and ST emission plots suggests that the P-F emission and ST emission mechanisms do not contribute to the leakage current behavior of the 0.75BF-0.25BT ceramics. Subsequently, F-N tunneling is observed under a high electric field in the as-sintered 0.75BF-0.25BT ceramics, whereas the direct tunneling effect is exhibited throughout the measured electric field in the quenched ceramics. The SCLC mechanism is dominant in both the as-sintered and quenched 0.75BF-0.25BT ceramics. A change from Ohmic conduction to trap-filled-limit conduction is observed with an increase in the applied electric field in the as-sintered ceramics, whereas the quenched ceramics only revealed Ohmic conduction over the entire range of the measured electric field. The different behaviors exhibited in the SCLC mechanism between the as-sintered and the quenched ceramics imply that the conduction mechanism can be controlled by heat treatment.

Automated summary

The leakage current mechanism in the 0.75BF-0.25BT ceramics is mainly controlled by the SCLC mechanism, with differences between the sintered and quenched ceramics potentially influenced by heat treatment. The study also revealed that the P-F emission and ST emission mechanisms did not contribute to the leakage current behavior.