钙钛矿锰氧化物低维纳米结构研究进展

钙钛矿结构锰氧化物由于同时存在电荷、自旋、轨道、晶格等多种自由度, 它们之间很强的相互作用和相互竞争导致了一系列新颖的物理现象, 如庞磁电阻效应、巨磁熵效应、绝缘体-金属转变、电子相分离、电荷/轨道有序等现象, 使其成为凝聚态物理学研究的热点。随着微电子器件日趋集成化和微型化, 其特征尺寸越来越小, 目前基于钙钛矿结构锰氧化物微电子器件的特征尺寸已经进入纳米尺度。在纳米尺度钙钛矿结构锰氧化物具有显著的尺寸效应, 表现出与薄膜及块材不同的电、磁输运特性, 在新一代微电子器件领域具有重要的应用价值。近年来人们在钙钛矿锰氧化物低维纳米结构制备、电磁输运特性测量、微结构表征及理论模拟方面, 都取得了较大的研究进展, 本文对此进行了评述。首先, 概述了钙钛矿锰氧化物低维纳米结构的微结构研究进展; 介绍了钙钛矿锰氧化物低维纳米结构的电子相分离及电荷有序现象; 评述了其电磁输运特性的纳米尺度表征; 讨论了钙钛矿锰氧化物低维纳米结构在自旋电子学、磁随机存储器和传感器方面的应用进展。最后指出了未来钙钛矿锰氧化物低维纳米结构研究需要重点解决的一些问题。

Advances on Low-dimensional Perovskite Manganite Nanostructures

In the perovskite-type manganese oxides, multi-degrees of freedom such as charge, spin, orbital and crystal lattice coexist simultaneously, and the strong completing interactions among them result in a series of novel physical phenomena such as colossal magnetoresistance effect, giant magnetic entropy effect, metal-insulator transition, electronic phase separation and charge/orbital ordering, which make them become attractive issues in condensed matter physics. Advances in integration and miniaturization of the electronic devices have resulted in their feature sizes continued to be decreased, and now the feature sizes of electronic devices based on perovskite-type manganese oxides are down-scaled into nanometered sizes. At nanoscale perovskite-type manganese oxides exhibit apparent size effects and possess the electrical and magnetic transport properties that are different from their bulk and film counterparts, which have important applications in the fields of a new generation of microelectronic devices. In recent years, many advances have been made in fabrication, microstructural characterization electrical and magnetic property measurements of the low-dimensional perovskite manganite nanostructures, and also in the theoretical modelling of the resulting properties. In this paper, an overview of the state of art in the low-dimensional perovskite manganite nanostructures is presented. First, the microstructural characterizations of the low-dimensional perovskite manganite nanostructures are reviewed, and then the electronic phase separation and charge ordering phenomena in the low-dimensional perovskite manganite nanostructures are also introduced. Measurements of the electrical and magnetic transport properties at nanoscale are reviewed. Their potential applications in the fields of spintronics, the next-generation magnetic random access memories and gas sensors, are also discussed. Finally, some key problems in the future researches of the low-dimensional perovskite manganite nanostructures are also outlined.