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Caption : (a) photograph of the ti/tio2/ti samples fabricated on a thermally oxidized titanium foil, and (b) the schematic diagram of a single memory device; the plan view (i) and the cross-sectional (ii) sem micrographs of the oxide layer are given as insets. 

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Caption : (a) the block diagram of the experimental setup utilized for the i-v measurements, and (b) a photograph of the fabricated device placed on the stage of a x-y-z micromanipulator for electrical characterization.

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Caption : (a)-(i) the i-v plots evolution due to the stated dc biasing voltages, recordings are carried out by utilizing an ac voltage of +/-1.5 v at 40 hz for voltage sweeping. 

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Caption : (a)-(i) the deformation of the i-v plots of a 1.0 v biased device due to the variation of the voltage sweeping frequencies; graphically the frequency range of 30 to 60 hz is determined to be suitable for the device tests. 

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Caption : (a) the long-term stability of the device after receiving a write pulse, and (b) demonstrating the current variations just after the write action by utilizing a magnified time scale.  

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Caption : spike-timing-dependent plasticity obtained experimentally for the fabricated memristor; (a) depressing and (b) potentiation.