Whirling spin order in the quasicrystal approximant Au72Al14Tb14

Abstract

A neutron powder diffraction experiment has been performed on the quasicrystal approximant Au72Al14Tb14, a body-centered-cubic crystal of icosahedral spin clusters. The long-range antiferromagnetic order was confirmed at the transition temperature TN=10.4 K. The magnetic structure consists of noncoplanar whirling spins on the icosahedral clusters, arranged in an antiferroic manner. A simple icosahedral spin-cluster model with uniaxial anisotropy accounts well the whirling spin order as well as the in-field metamagnetic transition, indicating that the icosahedral symmetry is essential. ©2019 American Physical Society