1. Superconducting YAu 3 Si and Antiferromagnetic GdAu 3 Si with an Interpenetrating Framework Structure Built from 16-Atom Polyhedra.
- Author
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Gebresenbut GH, Eriksson L, Häussermann U, Rydh A, Mathieu R, Vekilova OY, and Shiino T
- Abstract
Investigations of reaction mixtures RE
x (Au0.79 Si0.21 )100- x (RE = Y and Gd) yielded the compounds REAu3 Si which adopt a new structure type, referred to as GdAu3 Si structure ( tP 80, P 42 / mnm , Z = 16, a = 12.8244(6)/12.7702(2) Å, and c = 9.0883(8)/9.0456(2) Å for GdAu3 Si/YAu3 Si, respectively). REAu3 Si was afforded as millimeter-sized faceted crystal specimens from solution growth employing melts with composition RE18 (Au0.79 Si0.21 )82 . In the GdAu3 Si structure, the Au and Si atoms are strictly ordered and form a framework built of corner-connected, Si-centered, trigonal prismatic units SiAu6 . RE atoms distribute on 3 crystallographically different sites and each attain a 16-atom coordination by 12 Au and 4 Si atoms. These 16-atom polyhedra commonly fill the space of the unit cell. The physical properties of REAu3 Si were investigated by heat capacity, electrical resistivity, and magnetometry techniques and are discussed in the light of theoretical predictions. YAu3 Si exhibits superconductivity around 1 K, whereas GdAu3 Si shows a complex magnetic ordering, likely related to frustrated antiferromagnets exhibiting chiral spin textures. GdAu3 Si-type phases with interesting magnetic and transport properties may exist in an extended range of ternary RE-Au-Si systems, similar to the compositionally adjacent cubic 1/1 approximants RE(Au,Si)∼6 .- Published
- 2022
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