Nd0.7Sr0.3MnO3陶瓷中界面“陷阱态”相关电阻转变行为

通过固相烧结和高能球磨后热处理两种方法分别得到不具晶(相)界和具有明显晶(相)界的两种Nd_0.7Sr_0.3MnO₃陶瓷样品, 并用两线法和四线法分别对这两种样品的电极-块体接触界面和晶(相)界界面的I-V和电脉冲诱导电阻转变效应(EPIR)进行研究. 结果发现, 在两线法测试下, 电极-块体界面具有回滞的非线性I-V特征, 并能产生稳定的EPIR效应, EPIR的稳定性随温度的升高逐渐减弱并消失; 而对具有明显晶(相)界的陶瓷样品, 四线法测试结果表明, 虽然其I-V行为也具有非线性和回滞性特点, 但不能产生EPIR 效应. 这些奇特的界面输运行为与界面中的各种缺陷充当“陷阱”并实现对载流子的捕捉和释放过程密切相关. 而大量的晶(相)界界面及其复杂的连接方式导致较大的漏导则是晶(相)界不能出现EPIR效应的主要原因.

Interfacial trap dependent resistance switching effect in Nd0.7Sr0.3MnO3 ceramic

Switching behavior in Nd_0.7Sr_0.3MnO₃ ceramic is investigated widely due to its close association with the new storage Resistive random access memory. In this work, we discuss the transport characteristic of the electrode-bulk interface and boundary/phase interface, and explain the differences between the two interfaces. Firstly, the Nd_0.7Sr_0.3MnO₃ ceramic samples are prepared by solid-phase reaction and high-energy milling methods, respectively. And the transport properties of the two interfaces are investigated respectively by the two-line and four-line measurements. The results show that the Ag electrode-bulk interfaces exhibit nonlinear and hysteretic I-V characteristics and a stable resistance switching effect, and the stability of resistance switching behavior is reduced gradually with the increase of temperature. For the boundaries/phase interfaces, however, it does not exhibit resistance switching effect, although a nonlinear and hysteretic I-V behavior can also be observed under the four-line measurement mode. Various defects in the two interfaces act as traps and regulate the interfacial transports and result in the nonlinear and hysteretic I-V behaviors in the two interfaces. Additionally, the simulation experiments reveal that a large number of boundaries/phase interfaces and larger leakage conductance resulting from the complex connections of boundaries/phase interfaces are the main responsibilities for the fact that the boundaries/(phase) interfaces do not exhibit EPIR behavior as the electrode-bulk interface.