Dramatic Switching of Magnetic Exchange in a Classic Transition Metal Oxide: Evidence for Orbital Ordering

TL;DR

This paper investigates the spin correlations in V2O3 across metallic and insulating phases, revealing an abrupt change in magnetic order during the transition, supporting the idea of an orbital ordering transition.

Contribution

It provides experimental evidence linking magnetic exchange switching to orbital ordering in V2O3, a classic transition metal oxide.

Findings

Metallic samples show incommensurate spin correlations with little doping dependence.

Insulating samples exhibit near-neighbor spin correlations.

Transition to antiferromagnetic insulator involves an abrupt change in magnetic order.

Abstract

Spin correlations in metallic and insulating phases of $V_2O_3$ and its derivatives are investigated using magnetic neutron scattering. Metallic samples have incommensurate spin correlations varying little with hole doping. Paramagnetic insulating samples have spin correlations only among near neighbors. The transition from either of these phases into the low temperature insulating antiferromagnetic phase is accompanied by an abrupt change of dynamic magnetic short range order. Our results support the idea that the transition into the antiferromagnetic insulator is also an orbital ordering transition.