Abstract
In this work, we show ionic liquid field-effect of La0.8Ba0.2MnO3 (LBMO) untrathin films prepared by the sol-gel method. When applying a positive gate voltage (V
g) in vacuum, it is found that the film resistivity continuously increases tenfold within hours or minutes depending on the magnitude of V
g, accompanied with disappearance of the low-temperature metallic transport behavior. In contrast, the film resistivity changes little in air or under a negative applied V
g. Such a difference reveals that the increased resistivity is related to the oxygen depletion in the films under the positive V
g, especially at the grain boundaries. After removing the positive V
g in vacuum, the room-temperature resistivity begins to fall off and the low-temperature metallic state is partially restored in several tens hours, suggesting oxygen diffusion from the relatively oxygen-rich grains to the seriously oxygen-deficient grain boundaries. Furthermore, the oxygen content in the oxygen-deficient films can be almost fully restored in ten minutes by external annealing (200 °C) or Joule self-heating (21 mA) the films in air. These experimental findings provide an additional method in tuning oxygen vacancies in transition-metal oxide films.
Funder
National Natural Science Foundation of China
Publisher
The Electrochemical Society
Subject
Electronic, Optical and Magnetic Materials