Neutron scattering study of dipolar spin ice (formula presented)Frustrated pyrochlore magnet

Abstract

By means of neutron scattering techniques we have investigated the frustrated pyrochlore magnet (formula presented) which was found to show ferromagnetic spin-ice behavior below (formula presented) by susceptibility measurements. High-resolution powder neutron diffraction shows no detectable disorder of the lattice, which implies the appearance of a random magnetic state solely by frustrated geometry, i.e., the corner sharing tetrahedra. Magnetic inelastic scattering spectra show that Ho magnetic moments behave as an Ising spin system at low temperatures and that the spin fluctuation has static character. The system remains in a short-range-ordered state down to at least (formula presented) By analyzing the wave-vector dependence of the magnetic scattering using a mean-field theory, it is shown that the Ising spins interact via the dipolar interaction. Therefore we conclude that (formula presented) belongs to the dipolar-spin-ice family. Slow spin dynamics is exhibited as thermal hysteresis and time dependence of the magnetic scattering. © 2002 The American Physical Society.