Chemists overturn 40-year assumption about a key class of superconductors

Amazing stuff!

"Scientists at Warwick have shown that a material treated for 40 years as a uniform, textbook superconductor is in fact a patchwork of different crystal structures throughout its bulk, using an advanced 3D imaging technique to see deep inside the crystal for the first time. ...

What they found was a crystal divided into regions with two subtly different atomic arrangements, separated by boundaries hundreds of times wider than anyone expected to see between two crystal structures. These boundaries were so wide that they behaved almost like a structure in their own right, rather than a simple dividing line. ..."

From the abstract:

"Structural phase transitions generate complex microstructures that often govern material functionality, yet directly resolving their three-dimensional organization in bulk samples remains challenging.

Here we employ scanning three-dimensional x-ray diffraction (3DXRD) to resolve the bulk microstructure of La1.675⁢Eu0.2⁢Sr0.125⁢CuO4 , a prototypical 1/8-doped cuprate in which structural and electronic heterogeneity is well established.

We reveal remarkably broad tetragonallike domain wall regions within the nominally orthorhombic crystal structure, and, upon cooling to 100 K, a fine microstructure of orthorhombiclike stripes embedded within the tetragonal matrix that has significant consequences for interpreting the interplay between structural and electronic heterogeneity in this class of materials. More broadly, this work establishes 3DXRD as a powerful approach for resolving bulk microstructures and understanding their role in emergent functionality."

Chemists overturn 40-year assumption about a key class of superconductors

Warwick chemists overturn 40-year assumption about a key class of superconductor (original news release) "Scientists have shown that a material treated for 40 years as a uniform, textbook superconductor is in fact a patchwork of different crystal structures throughout its bulk, using one of the latest 3D imaging techniques to see deep inside the crystal for the first time."

Giant Domain Walls and Intrinsic Heterogeneity in 214 Cuprate Superconductors (open access)

Fig. 2.

(a) Spatially resolved maps of Γ4+ at 300, 140, 120, and 100 K, illustrating the temperature evolution of the structural domains.

(b) Histograms of Γ4+ at corresponding temperatures, showing the transition from bimodal at 300 K to a more homogeneous but still asymmetric distribution at 100 K.

(c) Maps of the absolute strain magnitude |Γ4+| with 

(d) showing enhanced maps and line profiles ...