Resolving the microscopic nature of electronic phase separation in the CMR manganites via 3DXRD

Colossal magnetoresistance (CMR) in the manganite perovskites arises from intrinsic electronic phase separation (EPS) occurring because of the competition between ferromagnetic conducting and antiferromagnetic orbitally ordered insulating phases, at specific doping levels. However, the very nature of the EPS state has frustrated any attempts over the past 3 decades to accurately characterise the microscopic structures of its constituents. We propose a diffraction resolved tomography experiment with nano-focused beam on ID11 to tackle this long-standing problem. The results will allow for accurate microscopic structural models of the competing states to be ascertained for the first time and will also provide a 3-dimensional map of strain fields within the electronically separated phases on a 0.1-100 μm length scale. Our insights will lead to a broader understanding of how these functional properties are linked with EPS phenomena so that these can be systematically tuned and enhanced.

钙钛矿锰氧化物中的巨磁电阻（CMR）源于特定掺杂水平下铁磁导电相与反铁磁轨道有序绝缘相之间的竞争所引发的本征电子相分离（EPS）。然而，EPS态的本质特性在过去30年里一直阻碍着对其组分微观结构进行精确表征的所有尝试。我们提出在ID11装置上采用纳米聚焦光束开展衍射分辨断层扫描实验，以解决这一长期存在的难题。实验结果将首次使竞争态的精确微观结构模型得以确立，并提供电子分离相内应变场在0.1-100 μm尺度上的三维分布图。我们的研究见解将助力更深入地理解这些功能特性与EPS现象之间的关联，从而实现对其的系统性调控与优化。