Universität zu Köln

Pajerowski, Daniel M., Pratt, Daniel K., Hahn, Steven E., Tian, Wei, Granroth, Garrett E., Kolesnikov, Alexander, I, Taskin, Alexey A., Ando, Yoichi ORCID: 0000-0002-3553-3355 and McQueeney, Robert J. (2020). Spin waves above and below the Verwey transition in TbBaFe2O5. Phys. Rev. B, 101 (6). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

TbBaFe2O5+delta (TBFO) is a mixed valence compound with an antiferromagnetic order (T-N = 450 K) that changes along with the crystal structure and conductivity upon cooling below a Verwey-like transition (T-v = 280 K). 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 = 4 K < T-v and T = 320 K > T-v are modeled with linear-spin-wave theory to extract anisotropy and superexchange parameters. Below T-v, we observe a sizable magnon gap due to an easy-axis magnetic anisotropy that closes above T v due to the evolution of easy-plane anisotropy. The magnetic interactions are found to be highly three-dimensional and change across T-v. Above T-v, where the conductivity is greater, a damping term is required to model the spin waves that suggests a coupling to valence fluctuations.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Pajerowski, Daniel M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pratt, Daniel K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hahn, Steven E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Tian, Wei UNSPECIFIED UNSPECIFIED UNSPECIFIED Granroth, Garrett E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kolesnikov, Alexander, I UNSPECIFIED UNSPECIFIED UNSPECIFIED Taskin, Alexey A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ando, Yoichi UNSPECIFIED orcid.org/0000-0002-3553-3355 UNSPECIFIED McQueeney, Robert J. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-344645
DOI:	10.1103/PhysRevB.101.064418
Journal or Publication Title:	Phys. Rev. B
Volume:	101
Number:	6
Date:	2020
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics II
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CHARGE; MAGNETIZATION; VISUALIZATION; MAGNETITE; CRYSTAL Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/34464