Fig. 5: Modulation of electrical resistance of SFCO films by protonation and de-protonation. | Nature Communications

Fig. 5: Modulation of electrical resistance of SFCO films by protonation and de-protonation.

From: Stabilization of oxygen vacancy ordering and electrochemical-proton-insertion-and-extraction-induced large resistance modulation in strontium iron cobalt oxides Sr(Fe,Co)Oy

Fig. 5

a Gate voltage VGS sequence used in our measurements. The illustration at the top shows VGS pulses with durations of 20 s that were repeatedly applied to induce protonation and de-protonation of SFCO films. The total duration of positive and negative VGS pulses for protonation and de-protonation reactions was 200 s. In the interval of VGS pulses, the channel resistance RDS was acquired with a source-drain voltage VSD of 0.1 V and without VGS applied. The bottom graph in the figure shows typical RDS data measured with the VGS sequence. b Change in RDS for SrFeO2.8, Sr(Fe0.5Co0.5)O2.5, and SrCoO2.5 film channels induced by applying VGS = ± 2.0 V and ± 2.5 V. The data were taken for the transistor device with 2-mm-wide and 1 mm-long channels. c Co concentration dependence of the SFCO channel resistance before VGS application (RDS in the as-grown state) and the magnitude of the resistance change ΔR induced by application of VG = ± 2.0 and ± 2.5 V. ΔR is defined by the ratio of RDS obtained after applying the last pulse of each positive (or negative) VGS sequence (ΔR = RHigh/RLow, see Fig. 5a).

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