Denoel Fernand, Huang Yu-Chin, Kondedan Neha, Rydh Andreas, Pay Gómez Cesar, Mathieu Roland
Department of Materials Science and Engineering, Uppsala University, Box 35, Uppsala, 751 03, Sweden.
Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala 751 21, Sweden.
Inorg Chem. 2024 Mar 18;63(11):5040-5051. doi: 10.1021/acs.inorgchem.3c04500. Epub 2024 Mar 1.
The effect of Eu doping in the Tsai quasicrystal (QC) GdCd and its periodic 1/1 approximant crystal (AC) GdCd are investigated. This represents the first synthesis of Eu-containing stable QC samples, where three samples with the final composition GdEuCd at Eu doping concentrations = 0.06, 0.13, and 0.19 are obtained (α ∼ 0.2). They are compared to two 1/1 ACs with compositions GdEuCd ( = 0.12, 0.16). In addition, a new type of 1/1 AC, differing only by the inclusion of extra Cd sites unique to the EuCd 1/1 AC, has been discovered and synthesized for the concentrations GdEuCd ( = 0.25, 0.33, 0.45, 0.69, 0.73, and 0 < δ ≤ 0.085). Due to the preferred cube morphology of its single grains, we refer to them as c-type 1/1 ACs and to the conventional standard ones as s-type. In both QCs and s-type ACs, the Eu content appears to saturate at a concentration of ∼20%. On the other hand, any Gd| Eu ratio is allowed in the c-type ACs, varying continuously between GdCd and EuCd. We describe and contrast the changes in composition, atomic structure, specific heat, and magnetic properties induced by Eu doping in the quasicrystalline phase and the s-type and c-type 1/1 ACs. By comparing our results to the literature data, we propose that the occupancy of the extra Cd sites can be used to predict the stability of Tsai-type quasicrystalline phases.
研究了铕（Eu）掺杂对蔡氏准晶体（QC）GdCd及其周期性1/1近似晶体（AC）GdCd的影响。这代表了首次合成含铕的稳定QC样品，得到了最终组成为GdEuCd且铕掺杂浓度分别为0.06、0.13和0.19的三个样品（α ∼ 0.2）。将它们与两个组成为GdEuCd（ = 0.12、0.16）的1/1 AC进行比较。此外，还发现并合成了一种新型的1/1 AC，其与EuCd 1/1 AC的区别仅在于包含额外的镉（Cd）位点，其浓度为GdEuCd（ = 0.25、0.33、0.45、0.69、0.73，且0 < δ ≤ 0.085）。由于其单晶粒具有优选的立方形态，我们将它们称为c型1/1 AC，而将传统标准的称为s型。在QC和s型AC中，铕含量在浓度约为20%时似乎达到饱和。另一方面，在c型AC中允许任何Gd|Eu比例，在GdCd和EuCd之间连续变化。我们描述并对比了准晶相以及s型和c型1/1 AC中铕掺杂引起的成分、原子结构、比热和磁性的变化。通过将我们的结果与文献数据进行比较，我们提出额外Cd位点的占有率可用于预测蔡氏型准晶相的稳定性。
