Publication Date

2-1-2020

Department

Ames Laboratory; Physics and Astronomy

Campus Units

Ames Laboratory, Physics and Astronomy

OSTI ID+

1600077

Report Number

IS-J 10171

DOI

10.1103/PhysRevB.101.064418

Journal Title

Physical Review B

Volume Number

101

Issue Number

6

First Page

064418

Abstract

TbBaFe2O5+δ (TBFO) is a mixed valence compound with an antiferromagnetic order (TN=450K) that changes along with the crystal structure and conductivity upon cooling below a Verwey-like transition (TV=280K). This type of double-cell-layered perovskite is useful to study putative charge ordering in fractional valence systems because the crystal structure develops unique sites for the different valence states. While the evolution of the static magnetic structure in the different charge ordered states of TBFO is known, in this study we investigate the effect of charge ordering on the magnetic interactions. Dispersive magnetic excitations measured using single crystal inelastic neutron scattering experiments at T=4KTV are modeled with linear-spin-wave theory to extract anisotropy and superexchange parameters. Below TV, we observe a sizable magnon gap due to an easy-axis magnetic anisotropy that closes above TV due to the evolution of easy-plane anisotropy. The magnetic interactions are found to be highly three-dimensional and change across TV. Above TV, where the conductivity is greater, a damping term is required to model the spin waves that suggests a coupling to valence fluctuations.

DOE Contract Number(s)

AC05-00OR22725

Language

en

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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