Abstract
Our powder inelastic neutron scattering data indicate that is a system of spin chains that are three-dimensionally tangled in the cubic phase above 50 K due to randomly occupied orbitals of () ions. Below 50 K in the tetragonal phase, the chains become straight due to antiferro-orbital ordering. This is evidenced by the characteristic wave vector dependence of the magnetic structure factor that changes from symmetric to asymmetric at the cubic-to-tetragonal transition.
- Received 29 March 2004
DOI:https://doi.org/10.1103/PhysRevLett.93.156407
©2004 American Physical Society