多铁性材料的超高分辨扫描探针热电显微术研究

The intigratition and microminiaturization of functional devices based on multiferroic materials can lead to the serious consumption and remarkably thermal effect in devices. Meanwhile, large leakage current can also remarkably limit the application of multiferroic matierals and devices. the At present the microsopic investigations of magnetoelectric materials limited to domain structures and their dynamic behaviors under external electric field and magnetic field, less work has been performed so far to study local thermal properties and local leakage currents of domain structures, as well as the integrated microscope techniques with respect to local thermal and electric properties. Therefore, it is of importance to investigate the nanoscale microstructure and local thermal and electric properties on multiferroic materials, which can reveal the interactional mechanism between nanodomains and their comprehensively phasical properties. In the planning project, scanning probe thermal-piezo microscopy will be firstly developed based on advanced scanning probe microscopy and the functional response between nano-thermal probe and nanodomains under external field, the local thermal and electric properties of nanodomain structures on multiferroic materials will be studied. Our research will provied a novel method with high resolution for characterizing microstructure and local physical properties, as well as understanding of novel physical effect on multiferroic materials.

以多铁性材料为基础的器件正朝着功能集成化，尺寸微型化方向发展，尺寸微型化易导致器件功耗严重、热效应显著。而较高的微区漏电流也是影响多铁性材料与器件应用的重要因素。但目前多铁性材料研究多局限于畴结构及其在电场/磁场下的动态演化行为，对畴结构微区热学性能及漏导特性的研究不多，特别缺乏是畴结构和微区热、电性能一体化表征技术。因此迫切需要在开展纳米尺度多铁性材料微结构以及相关微区热学、电学性能研究，以揭示纳米畴结构及其综合物性互作用机制。本课题拟在先进扫描探针显微术的基础上，针对多铁性材料纳米畴结构及微区热学/电学性能表征之急需，基于外场下纳米热学探针与纳米畴结构之间互作用物理功能响应，首次建立高分辨扫描探针热电显微术来开展多铁材料纳米畴结构及其热学/电学性能研究。本课题研究将为当前迅猛发展的多铁材料结构及微区综合物理性能表征提供一种纳米表征新方法，并为多铁功能材料新物理效应提供新的认识和理解。

本课题在先进扫描探针显微术的基础上，针对多铁性材料纳米畴结构及微区热学/电学性能表征之急需，基于外场下纳米热学探针与纳米畴结构之间互作用物理功能响应，建立了高分辨扫描探针热电显微术，拓展了AFM 功能模式，为评价多铁体材料纳米尺度畴结构及其机电和热学特性等综合物性研究提供了一种重要的、新型高分辨纳米表征新方法。利用SThPM原位表征了BiFeO3纳米畴结构及其机电和热学动态响应，以及不同沉积氧分压Mn-BiFeO3薄膜的极化动态响应及I-V特性研究，揭示了与薄膜中复合缺陷极化场密切关联的铁电畴极化反转及极化弛豫行为。本工作不仅丰富了多铁材料的学术内涵，而且有力地推动了扫描探针显微术的应用研究。