Superconducting YAu 3 Si and Antiferromagnetic GdAu 3 Si with an Interpenetrating Framework Structure Built from 16-Atom Polyhedra

• Published in: Inorganic chemistry Vol. 61; no. 10; pp. 4322 - 4334
• Main Authors: Gebresenbut, Girma Hailu, Eriksson, Lars, Häussermann, Ulrich, Rydh, Andreas, Mathieu, Roland, Vekilova, Olga Yu, Shiino, Takayuki
• Format: Journal Article
• Language: English
• Published: United States 14-03-2022
• ISSN: 0020-1669; 1520-510X; 1520-510X
• DOI: 10.1021/acs.inorgchem.1c03456

Investigations of reaction mixtures RE
(Au
Si
)
(RE = Y and Gd) yielded the compounds REAu
Si which adopt a new structure type, referred to as GdAu
Si structure (
80,
4
/
,
= 16,
= 12.8244(6)/12.7702(2) Å, and
= 9.0883(8)/9.0456(2) Å for GdAu
Si/YAu
Si, respectively). REAu
Si was afforded as millimeter-sized faceted crystal specimens from solution growth employing melts with composition RE
(Au
Si
)
. In the GdAu
Si structure, the Au and Si atoms are strictly ordered and form a framework built of corner-connected, Si-centered, trigonal prismatic units SiAu
. 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 REAu
Si were investigated by heat capacity, electrical resistivity, and magnetometry techniques and are discussed in the light of theoretical predictions. YAu
Si exhibits superconductivity around 1 K, whereas GdAu
Si shows a complex magnetic ordering, likely related to frustrated antiferromagnets exhibiting chiral spin textures. GdAu
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)
.