Interfaces in {100} epitaxial heterostructures of perovskite oxides
Interfaces in {100} epitaxial heterostructures of perovskite oxides
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DOI：
10.1080/14786430600640460
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发表时间：
2006-05-21
影响因子：
1.6
通讯作者：
Colliex, C.
中科院分区：
文献类型：
--
作者：
Maurice, J. -L.;Imhoff, D.;Colliex, C.
准确的钙钛矿结构具有简单的立方对称性和组成ABO(3)，其中A是相对较大的阳离子，B是较小的阳离子。A和B阳离子的选择，以及在这两个位置上可能的取代，产生了大量共享相同碱基的材料，立方体的大小和形状的扭曲相对较小。此外，这些氧化物经常允许氧的非化学计量比有或没有顺序到几个百分点的量。由于它们的导电性、绝缘性、铁电性、磁性、超导性等特性，它们形成了大量具有重要技术意义的材料。钙钛矿氧化物的异质外延使人们能够在这些材料之间建立原子上尖锐的界面，从而设想一系列有用的异质结。外延也有可能被证明是有用的副作用：(1)它迫使一个不会自然发生的化学邻居，创造了一种二维的第三种材料，以及(2)它施加了横向应变。这两种效果都允许人们探索具有强烈二维特征的新奇的、有时是不可预见的特性。本文首先回顾了在钙钛矿的{100}表面和界面上积累的一些知识，重点介绍了可能用于未来全氧化物微电子学的性质。然后揭示了半金属La-2/3Sr(1/3)MnO(3)与绝缘体SrTiO_3之间的界面情况，它在磁隧道结的磁阻中起着关键作用。它特别介绍了彻底的电子能量损失光谱测量，揭示了这些物体的原子尺度、结构和电子性质。
The exact perovskite structure has simple cubic symmetry and composition ABO(3), where A is a relatively large cation and B a smaller one. The choices of A and B cations, and the substitutions possible on either site, generate a large variety of materials sharing the same base, with relatively small distortions of the size and shape of the cube. In addition, these oxides often allow oxygen non- stoichiometry with or without order to the amount of several percent. They form a vast set of technologically important materials due to their conducting, insulating, ferroelectric, magnetic, superconducting, etc., properties. Heteroepitaxy of perovskite oxides allows one to construct atomically sharp interfaces between these materials and therefore to envisage a set of useful heterojunctions. The epitaxy has side effects that may also prove useful: ( 1) it forces a chemical neighbouring that would not occur naturally, creating a two-dimensional third material, and ( 2) it imposes a lateral strain. Both of these effects allow one to explore novel, sometimes unforeseen, properties with a strong two-dimensional character. This paper first reviews some of the knowledge that has been accumulated on {100} surfaces and interfaces of perovskites, with an emphasis on properties that could be used in future all-oxide microelectronics. It then exposes the case of the interface between the half-metal La-2/3Sr(1/3)MnO(3) and the insulator SrTiO3, which plays a key role in the magnetoresistance of magnetic tunnel junctions. It particularly presents thorough electron energy loss spectroscopy measurements that uncover the atomic scale structural and electronic properties of these objects.