Structural Analysis of the Gd–Au–Al 1/1 Quasicrystal Approximant Phase across Its Composition-Driven Magnetic Property Changes

• Published in: Inorganic chemistry Vol. 62; no. 36; pp. 14668 - 14677
• Main Authors: Huang, Yu-Chin, Häussermann, Ulrich, Gebresenbut, Girma H., Denoel, Fernand, Pay Gómez, Cesar
• Format: Journal Article
• Language: English
• Published: American Chemical Society 11-09-2023
• ISSN: 0020-1669; 1520-510X; 1520-510X
• DOI: 10.1021/acs.inorgchem.3c01967

Gd14Au x Al86–x Tsai-type 1/1 quasicrystal approximants (ACs) exhibit three magnetic orders that can be finely tuned by the valence electron concentration (e/a ratio). This parameter has been considered to be crucial for controlling the long-range magnetic order in quasicrystals (QCs) and ACs. However, the nonlinear trend of the lattice parameter as a function of Au concentration suggests that Gd14Au x Al86–x 1/1 ACs are not following a conventional solid solution behavior. We investigated Gd14Au x Al86–x samples with x values of 52, 53, 56, 61, 66, and 73 by single-crystal X-ray diffraction. Our analysis reveals that increasing Au/Al ordering with increasing x leads to distortions in the icosahedral shell built of the Gd atoms and that trends observed in the interatomic Gd–Gd distances closely correlate with the magnetic property changes across different x values. Our results demonstrate that the e/a ratio alone may be an oversimplified concept for investigating the long-range magnetic order in 1/1 ACs and QCs and that the mixing behavior of the nonmagnetic elements Au and Al plays a significant role in influencing the magnetic behavior of the Gd14Au x Al86–x 1/1 AC system. These findings will contribute to improved understanding towards tailoring magnetic properties in emerging materials.