以Pt/Ti/SiO_2/Si为衬底,制备了具有电阻转变特性的Ti/La_(0.7)Ca_(0.3) MnO<3>(LCMO)/Pt结构器件.X射线衍射分析表明LCMO薄膜呈纳米晶或非晶态,扫描电子显微镜及原子力显微镜分析表明LCMO薄膜表面平整、光滑致密.电学测试结果表明Ti/LCMO/Pt结构具有明显的双极型"负"电阻转变特性,低电阻态的导电过程为空间电荷限制电流机制,高电阻态的导电过程为Poole-Frenkel发射机制.利用氧化还原反应的随机性和TiO_x中间层空间分布的不均匀性,定性地解释了高电阻态的不稳定性以及电流一电压曲线上的电流突变现象.
The La_(0.7)Ca_(0.3)MnO_3 (LCMO) thin films with resistive switching properties were grown on Pt(111)/Ti/SiO_2/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 cur-rent (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 electro-chemical reaction and the non-uniformity of TiO_x interlayer spatial distribution.
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