六方、正交及其混合相YMnO3阻变性能调控机理研究

Resistive switching devices based on the multiferroic materials are expected to be the next generation of the multifunction memory with a huge potential of application due to many advantages in ferroelectric, magnetism and nonvolatile memory. However, origins of the ferroelectric polarization, magnetization switching, lattice aberrance and resistive switching are not completely clear. It has been the bottle neck factor to constrain the wide use of the multiferroic resistive switching devices. This project proposes to create a novel strategy to fabricate hexagonal, orthorhombic and their mixed-phase structures of YMnO3 films based on the pulsed laser deposition technique. By means of theoretical calculation and experiment, we will study the structures, ferroelectrics, magnetisms and electrical transport properties of the hexagonal, orthorhombic and their mixed-phase structures of YMnO3 based devices. Through deeply exploring on the intrinsic and the non-intrinsic physics mechanisms, we will find the key factors which influence the performance of the YMnO3 resistive switching device. And then the performances of YMnO3 devices would be optimized. By contrast, this project will establish the regulatory mechanisms for the hexagonal, orthorhombic and their mixed-phase structures of YMnO3 based resistive switching devices. It can be referred to achieve the multifunction and high-performance memory devices.

多铁阻变存储器集铁电性、磁性和信息的非易失性优势为一身，是新一代多功能电子存储器理想材料。现阶段人们对铁电极化、磁性翻转、结构畸变与阻变效应耦合的机理掌握不够充分，成为制约多铁性阻变器件广泛应用的瓶颈因素。本项目据此提出，采用脉冲激光沉积技术制备高性能的六方、正交和混合相YMnO3薄膜，结合理论和实验方法，深入对比研究六方、正交和混合相三种结构的YMnO3基阻变器件的结构、铁电性、磁性及电学输运性质，系统揭示YMnO3基阻变器件的本征及非本征物理机制，解决影响器件阻变性能的关键问题。本项目的实施将建立起六方、正交和混合相YMnO3基阻变器件的性能调控机制，为进一步获得多功能、高稳定性的阻变器件提供参考。

阻变存储器具有存储密度大、擦写速度快、可多值存储、结构简单等优点，被认为是替代闪存实现商业化的新一代存储器。多种氧化物材料构建了不同的阻变存储器模型。然而，由于制备方法、测试仪器不同造成不同氧化物材料的阻变机理尚未明确，影响了该类器件的性能优化与广泛应用。项目采用脉冲激光沉积（PLD）技术，制备了具有代表性的二元、三元、四元氧化物NiO、YMnO3 (YMO) 和PrBa2Cu3O7 (PBCO)薄膜。在同一条件下研究了NiO、YMO和PBCO薄膜的阻变行为，使结果更具有普适性。主要研究内容包括：YMO薄膜台阶低能耗阻变存储器的性能与机制；NiO/FTO无电形成双极电阻开关和量子电导效应；通过载流子注入操控PBCO/NSTO界面阻变与超导转变。此研究发明了YMO薄膜台阶低能耗阻变存储器；发现了NiO/FTO器件的量子电导行为，提出了运用载流子注入实现PBCO薄膜的超导转变的新方法与结果；进一步明晰了NiO、YMO和PBCO薄膜阻变器件的物理机制，为开发和应用新型氧化物阻变存储器奠定了基础。