Conduction mechanisms in thin (0.6)BiFeO3-(0.4)PbTiO3 films

Leakage current is one of the major drawbacks for a proper electrical and dielectric characterization limiting applications of ferroelectric materials, especially considering thin films. In this sense, understanding the leakage current mechanisms in such systems is of utmost importance. Herein, high quality (0.6)BiFeO3–(0.4)PbTiO3 (BFPT) thin films (∼90 nm) on Pt/TiO2/SiO2/Si substrates were synthesized by dip-coating, and electrical, structural, and microstructural properties were investigated. Analysis based on current density measurements revealed that, for BFPT thin films below 100 nm, all related bulk-limited conduction mechanisms are absent. At this thickness regime, only electrode-limited mechanisms should be considered, and the Fowler-Nordheim mechanism was found to be the predominant mechanism for fields above 240 kV/cm. Besides, dielectric spectroscopy investigations revealed real dielectric constants varying from 28 to 26, with low tangent loss (from 8% to 12%) in the range of 10 kHz and 1 MHz. Such results contribute for the further development of a new generation of BFPT thin films looking for appliable materials as electronic devices, non-volatile ferroelectric memories, and energy harvesting.

Abstract licence: CC BY-NC

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