In materials chemistry, identifying common parameters that can organize magnetic ground states across complex intermetallic compounds remains a central challenge. Researchers have long used chemically tunable parameters to control magnetic properties. One is valence-electron concentration, commonly discussed as the electron-per-atom (e/a) ratio. The e/a ratio has been widely used to classify magnetic ground states in metallic systems such as Heusler alloys and approximant crystals.
In gold (Au)-based Tsai-type approximant crystals, the e/a ratio has been found to control magnetic ground states, including long-range antiferromagnetic (AFM) and ferromagnetic (FM) orders, as well as the spin-glass state. Tsai-type compounds are generally described as structures built from clusters with multiple shells, in which the moment-bearing rare-earth element occupies an icosahedral site. The predictive power of e/a, however, is limited across different alloy families and constituent elements. Given the potential of quasicrystal-based intermetallics as platforms for exploring emerging magnetic phenomena, researchers need reliable, experimentally accessible parameters to identify and guide the development of their magnetic properties.
To address this gap, a research team led by Assistant Professor Farid Labib of the Research Institute for Science and Technology at Tokyo University of Science (TUS), Japan, and Associate Professor Kazuhiro Nawa of the Institute of Multidisciplinary Research for Advanced Materials at Tohoku University, Japan, along with Professor Ryuji Tamura of TUS, investigated whether the lattice parameter could serve as a unified structural parameter for magnetic ground state selection in Tsai-type icosahedral compounds.
