Neutron scattering and X-ray diffraction on HoInCu4

The ternary rare-earth compounds RInCu4 (R=Gd, Dy, Ho and Er) show strong indications of frustration as manifested by measurements of magnetic susceptibility and specific heat. The crystal structure, in which the rare-earth ions occupy a face-centered cubic lattice, suggests the presence of geometrical frustration. In order to get further insight into the crystal and magnetic structure we performed X-ray diffraction measurements on flux-grown single crystals and neutron diffraction measurements on powder of HoInCu4. Single crystal X-ray diffraction data confirmed that the samples are fully ordered, all atoms occupy crystallographically independent sites and crystallize in the cubic AuBe5-structure. HoInCu4 exhibits magnetic order below TN=0.75 K as evidenced by heat capacity measurements. Neutron diffraction patterns were taken above and below the Neel temperature, indicating a commensurate magnetic structure with a propagation vector τ=(1 1/2 0) below TN as well as strong magnetic correlations in the paramagnetic state as expected in systems with strong frustration. (orig.)