S=2 quasi-one-dimensional spin waves in CrCl2

Abstract

We examine the magnetic excitation spectrum in the S = 2 Heisenberg antiferromagnet CrCl2. Inelastic neutron scattering measurements on powder samples are able to determine the significant exchange interactions in this system. A large anisotropy gap is observed in the spectrum below the N´eel temperature and the ratio of the two largest exchange constants is Jc=Jb = 4:51:6. However, no sign of a gapped quantum spin liquid excitation was found in the paramagnetic phase.