ANISOTROPIC SPIN CORRELATIONS IN THE ZN-MG-HO ICOSAHEDRAL QUASI-CRYSTAL

Neutron scattering experiments have been performed on the Zn-Mg-Ho ico sahedral quasicrystal using powder and single-crystalline samples. In contrast to a previous Letter [Charrier ct al., Phys. Rev. Lett. 78, 4 637 (1997)], the magnetic long-range order could not be detected in th e icosahedral quasicrystal. It instead exhibits highly anisotropic dif fuse scattering, which appears as satellite ridges of intense nuclear Bragg reflections, running parallel to the fivefold axis. The result s uggests that quasi-five-dimensional spin correlations develop on a six -dimensional hypercubic lattice.