2026-10-01 東京理科大学,科学技術振興機構,東北大学,東京大学,北海道大学,名古屋大学,京都大学,日本原子力研究開発機構,J-PARCセンター,総合科学研究機構
図1 非Heisenberg型Tsai型1/1近似結晶における磁気モーメントの模式図。 希土類元素の磁気モーメントは、周囲の原子が作る結晶電場（＊6）によって特定の方向を向きやすくなる。本研究では、こうした局所磁気異方性をもつTsai型化合物について、格子定数と磁気基底状態との間に共通した関係が存在することを明らかにした。
＜関連情報＞
- https://www.tus.ac.jp/today/archive/20260916_9165.html
- https://pubs.acs.org/jacsat/article/doi/10.1021/jacs.6c05709/5442115/Lattice-Parameter-Governs-Magnetic-Ground-State
格子定数がツァイ型金属間化合物の磁気基底状態の選択を決定する Lattice Parameter Governs Magnetic Ground State Selection in Tsai-Type Intermetallic Compounds
Farid Labib;Kazuhiro Nawa;Yusuke Nambu;Hiroyuki Takakura;Yoichi Ikeda;Kazuhiko Deguchi;Masato Matsuura;Asuka Ishikawa;Ryoichi Kajimoto;Kazuhiko Ikeuchi;Taku J. Sato;Ryuji Tamura
The Journal of the American Chemical Society Published:September 30, 2026
DOI:https://doi.org/10.1021/jacs.6c05709
Abstract
Identifying the key parameters that govern magnetic ground states in complex intermetallics remains a central challenge in materials chemistry. Although the valence-electron concentration (e/a) has frequently been used to classify magnetism in Tsai-type approximant crystals, its predictive power is limited across different alloy families and constituent elements. Here, we demonstrate that the lattice parameter serves as a unified structural parameter governing magnetic ground state selection in Tsai-type icosahedral compounds. Within the framework presented in this work, magnetic ground states collapse onto a single phase diagram that is independent of alloy family and rare-earth species: antiferromagnetic order emerges above a critical lattice parameter of ∼14.72 Å, whereas ferromagnetic order is stabilized within the intermediate range 14.62 Å ≲ a ≲ 14.72 Å. These results indicate that the lattice parameter serves as an experimentally accessible structural parameter that encodes the electronic information traditionally represented by e/a and thereby provides a unified description of magnetic ground state selection. The trends revealed in the present work provide a useful guideline for identifying compositions that may stabilize previously unexplored magnetic phases, including antiferromagnetic quasicrystals and hedgehog-like magnetic textures.
