Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, 230031, China.
Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, China.
Adv Mater. 2018 Dec;30(52):e1805353. doi: 10.1002/adma.201805353. Epub 2018 Oct 29.
Domain walls (DWs) in strongly correlated materials have provided fertile ground for the discovery of exotic phenomena, and controlling the formation of DWs is still a challenge. Here, it is demonstrated that a new type of structural DW can be induced in a series of manganite thin films, which are engineered to achieve a robust charge-ordering insulating (COI) ground state by selecting various films and substrates. The monoclinic domains are somewhat irregular in shape, and the corresponding DWs, taking the shape of closed loops, are ferromagnetic and metallic (FMM) at low temperatures. Remarkably, the DWs exhibit little dependence on temperature or magnetic field, due to the structural origins of the domains. Additionally, using magnetic force microscopy, the role played by DWs in the dynamics of the COI and FMM phases at the mesoscopic scale is revealed. They function as barriers, strictly confining the phase dynamics within each domain, reflecting the strong coupling of electronic phases with the lattice. Each domain exhibits binary occupation by a single pure phase, resulting in a quasi-periodic phase separation. The universal behaviors of the multiple engineered films elucidate the possibility of controlling the formation of DWs and tuning phase dynamics through DW design.
在强关联材料中，畴壁（DWs）为发现奇异现象提供了肥沃的土壤，而控制 DW 的形成仍然是一个挑战。在这里，通过选择各种薄膜和衬底，在一系列锰氧化物薄膜中可以诱导出一种新型结构 DW。这些畴壁的形状有些不规则，对应的 DW 呈现出低温下的铁磁和金属（FMM）性质。值得注意的是，由于畴壁的结构起源，DW 对温度或磁场的依赖性很小。此外，通过磁力显微镜揭示了 DW 在 COI 和 FMM 相的介观动力学中的作用。它们作为障碍，严格限制了每个畴内的相动力学，反映了电子相与晶格的强耦合。每个畴都表现出单一纯相的二元占据，导致准周期相分离。多个工程化薄膜的普遍行为阐明了通过 DW 设计控制 DW 的形成和调整相动力学的可能性。
