Reproducible Electro-resistance Memory Effect in Ag/La0.67Sr0.33MnO3 Thin Films
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1071-F09-12
Reproducible Electro-resistance Memory Effect in Ag/La0.67Sr0.33MnO3 Thin Films Lina Huang, Bingjun Qu, and Litian Liu Institute of Microelectronics, Tsinghua University, Beijing, 100084, China, People's Republic of ABSTRACT The hysteretic and reproducible electro-resistance memory effect has been investigated in epitaxial La0.67Sr0.33MnO3 (LSMO) films under DC-bias stress and voltage pulses. The biassensitive current-voltage characteristic of the Ag/LSMO system is distinctly nonlinear, asymmetric and hysteretic, which indicates the appearance of the resistive switching. The pulsed voltage amplitude and duration dependence of the nonvolatile resistive switch were also provided. Clear resistance switching cycles were observed at room temperature under voltage pulses of ±5V and ~150ns. Reproducible switching properties, involving voltage-induced stepwise resistance change, resistance state saturation, and pulse duration dependent multilevel switchable capability, demonstrate well controllability with respect to future nonvolatile random access memory applications. INTRODUCTION In the last decade, intensive efforts have been exerted to the unique room temperature electric-pulse-induced resistance (EPIR) change effect discovered in numerous transition-metaloxides, such as perovskite manganites [1-4], titanates [5,6], zirconates [7,8] and niobic oxides [911]. The resistance of the oxides can reversibly switch between two stable resistive states with applied short electric pulses of different polarity, and the modified resistance retains even after removing the pulse source. The fascinating features of the EPIR effect manifest a great potential for digital device applications, e.g. nonvolatile resistance random access memories (RRAM) with low power consumption, fast write and erase speed, simple device structure, and the possibility of easy scale-down [12]. As for the microscopic mechanism of the bi-stable resistive switching, various models have been proposed, involving field-driven lattice distortions [1], Schottky barriers with interfacial states [3], electrochemical migration at the metal-oxide interface [2,4], and phase separation, etc. However, the above models could not explain the whole experimental results of the resistive switching. It is hence of vital importance to systematically study the diverse behaviors of the resistive switch, which will provide another clue to understanding the effect. In the present study, the hysteretic and polarity-dependent resistive switch properties of AgLa0.67Sr0.33MnO3-SrTiO3 system were investigated. The nonlinear, asymmetric and hysteretic current-voltage characteristic indicates the appearance of the resistive switching, and the reproducible switching properties share strong dependence on different selections of pulse parameters, thus demonstrating flexible controllability and multilevel storage capability as for future nonvolatile memory applications. EXPERIMENT 200nm thick LSMO films were grown on (001) SrTiO3 (STO) single crystal substrates by a pulsed laser de
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