点接触金属/Pr$lt;sub$gt;0.7$lt;/sub$gt;Ca$lt;sub$gt;0.3$lt;/sub$gt;MnO$lt;sub$gt;3$lt;/sub$gt;/Pt结构稳定的低电流电阻开关特性

利用自主开发的导电原子力显微镜控制Pt，W探针构成点接触金属/Pr_0.7Ca_0.3MnO₃（PCMO）/Pt三明治结构，对其电流-电压（I-V）及脉冲诱导电阻开关（EPIR）特性进行了研究.研究发现，在10 nA限流下两种电极对应结构的I-V都表现出相当稳定的双极性电阻开关特性，以及大于100的电阻开关比.进一步测试发现，点接触W/PCMO/Pt器件具有在10 nA限流下稳定的EPIR特性以及100 pA限流下重复的双极性电阻开关特性.此电流比已报道的电流低3个数量级，表明此结构在低功耗存储器件方面的潜在应用.通过对比样品不同位置、不同限流、不同接触面积点接触Pt/PCMO/Pt的I-V回滞特性，把点接触器件在低电流下稳定、显著的电阻开关效应归结于小的器件面积导致强的局域电场加强了O离子迁移效应.关键词：脉冲诱导电阻开关电场下氧离子迁移电阻开关

Reproducible low-current resistive switching of metal/Pr0.7Ca0.3MnO3/Pt junctions with a point-contact top electrode

Current-voltage （I-V） and the electrical pulse induced resistive switching （EPIR）characteristics of metal/Pr_0.7Ca_0.3MnO₃/Pt sandwich structures, where the metal is a point-contact Pt or W electrode, are investigated by using a home-made conductive AFM. The structures with both Pt and W tips behaves as rather reproducible bipolar resistive switching （RS） with an RS ratio larger than 100. However W/Pr_0.7Ca_0.3MnO₃/Pt structures shows EPIR under a compliance current of 10 nA and reproducible bipolar RS under a compliance current of 100 pA，which is about three orders lower than the published values and shows the potential applications in low power memory device. Further analysis of I-V characteristics at different positions of sample，under different current compliances， with different contact areas of device suggests that an enhanced oxygen vacancy migration due to point contact induced local intense electrical field， gives rise to a stable RS for Pt/Pr_0.7Ca_0.3MnO₃/Pt devices.