Orbital and spin chains in ZnV2O4

TL;DR

This study reveals that ZnV2O4 exhibits three-dimensionally tangled spin chains in the cubic phase above 50 K, which straighten into ordered chains below 50 K due to orbital ordering, as shown by neutron scattering data.

Contribution

The paper provides experimental evidence of orbital-driven spin chain reorganization in ZnV2O4 across a structural phase transition.

Findings

Spin chains are tangled in the cubic phase above 50 K.

Chains become straight below 50 K due to orbital ordering.

Wave vector dependence of magnetic structure factor changes at transition.

Abstract

Our powder inelastic neutron scattering data indicate that \zvo is a system of spin chains that are three dimensionally tangled in the cubic phase above 50 K due to randomly occupied $t_{2g}$ orbitals of V$^{3+}$ ($3d^2$) 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.