Researchers find heterogeneous structure in a cuprate superconductor — ScienceAlert
Researchers from the University of Warwick in the United Kingdom and the European Synchrotron Radiation Facility in France have concluded that the LESCO cuprate superconductor has a heterogeneous internal crystal structure. The results call into question an assumption that, since the discovery of cuprates in 1986, described them as materials with the same crystal structure throughout their entire volume, ScienceAlert reports.
Two structures inside the crystal
The scientists studied lanthanum-europium-strontium-copper oxide, known as LESCO. The sample was examined at temperatures from 300 kelvin, or about 26.9°C, to 100 kelvin, or approximately −173.2°C.
Three-dimensional X-ray diffraction (3DXRD) was used for the analysis. The method makes it possible to determine crystal structures inside a material by measuring strains at different points. This is the first study of the internal structure of a cuprate with such depth and detail, the source notes.
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The scans revealed two distinct atomic arrangements, separated by boundaries wider than those typical for such materials. According to the researchers, the crystal has a mosaic and textured structure, while the wide boundary regions may not merely coexist with superconductivity but hinder it.
Significance for models of superconductivity
The identified structural complexity may affect electron movement, their pairing, and the formation of ordered states in the material. The study’s authors suggest that this could explain differences in the properties of different cuprates.
In their assessment, some previous measurements of the bulk properties of such materials will need to be reconsidered, and future theoretical models should be built with structural heterogeneity in mind. The team plans to use 3DXRD to study other cuprates in order to determine how their internal structure affects their properties. The work was published in the journal Physical Review Letters.
