“…The present highly anisotropic magnetization curves in EuAu 5 and EuCu 5 are the first case as far as we know. For example, in the case of the magnetization curves in Eu-based ferromagnets such as EuPd 2 and EuPt 2 with the cubic structure [9] and EuRu 2 P 2 with the tetragonal structure [10], a saturated field is 4 -6 kOe for H ∥ ⟨100⟩, ⟨110⟩ and ⟨111⟩ in EuPd 2 , 7 -10 kOe for H ∥ ⟨100⟩, ⟨110⟩ and ⟨111⟩ in EuPt 2 , and 6 -10 kOe for H ∥ [100], and [001] in EuRu 2 P 2 . As EuAu 5 and EuCu 5 are ferromagnets, revealing θ p ≃ T C , the present anisotropic magnetization is not due to the geometric frustrated magnetism of the triangular lattice in the hexagonal basal plane, but might be due to the anisotropic exchange interaction.…”