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Damping of antiferromagnetic spin waves by valence fluctuations in the double layer perovskite YBaFe2O5

S. Chang·P. Karen·M. P. Hehlen·F. R. Trouw·R. J. McQueeney
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Abstract

Inelastic neutron scattering experiments show that spin dynamics in the charge ordered insulating ground state of the double-layer perovskite YBaFe2O5 is well described in terms of eg superexchange interactions. Above the Verwey transition at TV = 308 K, t2g double exchange-type conduction within antiferromagnetic FeO2--BaO--FeO2 double layers proceeds by an electron hopping process that requires a spin flip of the five-fold coordinated Fe ions, costing an energy 5 S^2 of approximately 0.1 eV. The hopping process disrupts near-neighbor spin correlations, leading to massive damping of zone-boundary spin waves.

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S. Chang, P. Karen, M. P. Hehlen, F. R. Trouw, R. J. McQueeney. 2007-02-07. Damping of antiferromagnetic spin waves by valence fluctuations in the double layer perovskite YBaFe2O5. https://doi.org/10.1103/physrevlett.99.037202

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