Europhysics Letters (EPL) · 1992 · 136 citations · 8 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsMagnetic MaterialsSolid State PhysicsExchange InteractionsMagnetic OxidesMagnetic Properties Of SolidsMagnetism In SolidsPerovskite MaterialsPhase TransitionsElectronic CorrelationsMagnetic Exchange InteractionsMagnetic Ordering TransitionsMagnetic PerovskitesMetal-insulator TransitionOrdering PhenomenaSpin-density Wave FormationSpin-density Waves
The metal-insulator transition in the orthorhombic perovskites PrNiO3 and NdNiO3 is accompanied by the sudden 3D magnetic ordering of the Ni ions (μNi ≈ 0.9 μB). The magnetic ground state, described by a commensurate κ = (1/2, 0, 1/2) spin density wave, is unprecedented in a perovskite structure. The coexistence of F and AF interactions suggests the existence of an orbital superlattice. This results from the breakdown of the degeneracy of the NiIII (t2g6 eg1) state due to electronic correlations. The gap is probably of charge-transfer type rather than originated by the exchange interactions.
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