Abstract
We present a neutron-diffraction study of FeV2O4, which is rare in exhibiting spin and orbital degrees of
freedom on both cation sublattices of the spinel structure. Our data confirm the existence of three structural
phase transitions previously identified with x-ray powder diffraction and reveal that the lower two transitions
are associated with sequential collinear and canted ferrimagnetic transitions involving both cation sites. Through
consideration of local crystal and spin symmetry, we further conclude that Fe2+ cations are ferro-orbitally ordered
below 135 K and V3+ orbitals order at 60 K, in accordance with predictions for vanadium spinels with large
trigonal distortions and strong spin-orbit coupling. Intriguingly, the direction of ordered vanadium spins at low
temperature obey “ice rules” more commonly associated with the frustrated rare-earth pyrochlore systems.
