超大各向异性磁电阻效应调控与机理研究

项目名称： 超大各向异性磁电阻效应调控与机理研究

项目编号： No.11274321

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 李润伟

作者单位： 中国科学院宁波材料技术与工程研究所

项目金额： 95万元

中文摘要： 基于各向异性磁电阻效应（AMR）的磁性传感器具有制备工艺简单、成本低等优点，在信息技术领域得到广泛应用。与巨磁电阻效应（GMR）相比，传统铁磁性材料中的AMR数值较小，导致AMR器件的灵敏度低于GMR器件。我们在钙钛矿型锰氧化物中发现了超大的AMR效应，比传统的AMR效应的数值大两个数量级。超大AMR材料的利用将会弥补传统AMR器件灵敏度偏低的缺点。但目前人们还没有在室温低磁场下获得超大的AMR效应，对超大AMR效应的物理机制及其调控方法尚不清楚。本项目选择电荷轨道有序的锰氧化物作为研究重点，研究超大AMR效应与金属-绝缘体转变、自旋/电荷轨道序转变、以及与相分离的内在关联规律与机制，在临界条件下研究磁场、电场、尺度/维度、以及应力等因素对超大AMR效应的调控规律，找出影响超大AMR数值、工作温度以及磁场灵敏度的关键因素，获得室温下可用的超大AMR材料，为研发下一代AMR器件奠定基础。

中文关键词： 锰氧化物；各向异性磁电阻；电子结构；；

英文摘要： Magnetic sensors based on anisotropic magnetoresistance effect (AMR) has widely used in the IT field due to their some advantages, such as a simple preparation and low cost. Compared to the giant magnetoresistance effect (GMR), the AMR value in conventional ferromagnetic materials is small, resulting in the sensitivity of AMR devices is usually inferior to that of GMR devices. In perovskite manganites, we found a colossal AMR effect, which is two orders of magnitude larger than the conventional AMR effect. It is expected the devices base on the colossal AMR effects will indicate high sensitivity. However, the colossal AMR effect has not yet been obtained at room temperature and under a low magnetic field, and also the physical mechanism and modulation methods of the colossal AMR effect remain unclear so far. In this project, we select orbital/charge ordered manganites to investigate the relevance between the colossal AMR effect and the metal-insulator transition，orbital/charge/spin ordering transition，and phase separation. We will try to modulate the colossal AMR effects in critical conditions by a magnetic field,electric field, size/dimensionality effects,and also stress/strain effects, and then clarify the key factor determining the value, working temperature and magnetic field sensitivity of the colossal AMR,

英文关键词： manganites；anisotropic magnetoresistance effect；electronic structure；；