  The various magnetic orders observed in approximant crystals of Tsai-type
quasicrystal are important for deepening our understanding of mysterious
magnetism in quasicrystals. Using an icosahedral cluster model with
inter-cluster interactions, we give an intuitive explanation of the mechanism
of magnetic orders previously reported by classical Monte-Carlo simulations for
an approximant-crystal model describing a Gd-based Tsai-type 1/1 approximant
crystal.

Materials Science