Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Nat Commun. 2013;4:2336. doi: 10.1038/ncomms3336.
The interplay between antagonistic superconductivity and ferromagnetism has been a interesting playground to explore the interaction between competing ground states. Although this effect in systems of conventional superconductors is better understood, the framework of the proximity effect at complex-oxide-based superconductor/ferromagnet interfaces is not so clear. The main difficulty originates from the lack of experimental tools capable of probing the interfaces directly with high spatial resolution. Here we harness cross-sectional scanning tunnelling microscopy and spectroscopy together with atomic-resolution electron microscopy to understand the buried interfaces between cuprate and manganite layers. The results show that the fundamental length scale of the electronic evolution between YBa2Cu3O(7-δ) (YBCO) and La2/3Ca1/3MnO3 (LCMO) is confined to the subnanometre range. Our findings provide a complete and direct microscopic picture of the electronic transition across the YBCO/LCMO interfaces, which is an important step towards understanding the competition between ferromagnetism and superconductivity in complex-oxide heterostructures.
反铁磁性和铁磁性之间的相互作用一直是探索竞争基态之间相互作用的有趣领域。尽管在传统超导体系统中对这种效应的理解更好，但基于复杂氧化物的超导体/铁磁体界面的近邻效应框架并不那么清楚。主要的困难源于缺乏能够以高空间分辨率直接探测界面的实验工具。在这里，我们利用横截面扫描隧道显微镜和光谱学以及原子分辨率电子显微镜来了解铜酸盐和锰酸盐层之间的埋层界面。结果表明，YBa2Cu3O(7-δ)（YBCO）和 La2/3Ca1/3MnO3（LCMO）之间电子演化的基本长度尺度限制在亚纳米范围内。我们的发现为 YBCO/LCMO 界面的电子跃迁提供了一个完整而直接的微观图像，这是理解复杂氧化物异质结构中铁磁性和超导性竞争的重要一步。
