Study on the "Negative" resistance switching properties in Ti/La0.7Ca0.3MnO3/Pt sandwiches devices

Abstract

The La0.7Ca0.3MnO3 (LCMO) thin films with resistive switching properties were grown on Pt(111)/Ti/SiO2/Si substrates by pulsed laser deposition (PLD). X-ray diffraction (XRD) results show that the films exhibited nanocrystalline or noncrystalline. Scanning electrical microscope (SEM) and atomic force microscope (AFM) were employed to characterize the morphology of as-grown films whose surfaces are flat, smooth and dense. The results of electrical test indicate that the Ti/LCMO/Pt structures show a bipolar 'negative' resistive switching behavior. The detailed analysis of current-voltage (I-V) curves domonstrate that the electrical conduction of the films at low resistance state is controlled by the space charge limited current (SCLC) mechanism, while that at high resistance state is controlled by Poole-Frenkel emission (PFE) mechanism. In the continuous I-V sweeping, the value of the high resistance state fluctuates more easily than that of the low resistance state. It is also found that the anomalous changes of current appear in the each I-V scan. All these results can be qualitatively explained by the combination of the randomness of electrochemical reaction and the non-uniformity of TiOx interlayer spatial distribution. Show more