Journal Article

FZJ-2018-02728

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Neutron diffraction study and theoretical analysis of the antiferromagnetic order and the diffuse scattering in the layered kagome system CaBaCo$_2$Fe$_2$O$_7$

Reim, J. (Corresponding author) ; Rosén, E.FZJ* ; Zaharko, O. ; Mostovoy, M. ; Robert, J. ; Valldor, M. ; Schweika, W.FZJ*

2018
Inst. Woodbury, NY

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Please use a persistent id in citations: http://hdl.handle.net/2128/18385  doi:10.1103/PhysRevB.97.144402

Abstract: The hexagonal swedenborgite, CaBaCo2Fe2O7, is a chiral frustrated antiferromagnet, in which magnetic ions form alternating kagome and triangular layers. We observe a long-range √3×√3 antiferromagnetic order setting in below TN=160 K by neutron diffraction on single crystals of CaBaCo2Fe2O7. Both magnetization and polarized neutron single crystal diffraction measurements show that close to TN spins lie predominantly in the ab plane, while upon cooling the spin structure becomes increasingly canted due to Dzyaloshinskii-Moriya interactions. The ordered structure can be described and refined within the magnetic space group P31m′. Diffuse scattering between the magnetic peaks reveals that the spin order is partial. Monte Carlo simulations based on a Heisenberg model with two nearest-neighbor exchange interactions show a similar diffuse scattering and coexistence of the √3×√3 order with disorder. The coexistence can be explained by the freedom to vary spins without affecting the long-range order, which gives rise to ground-state degeneracy. Polarization analysis of the magnetic peaks indicates the presence of long-period cycloidal spin correlations resulting from the broken inversion symmetry of the lattice, in agreement with our symmetry analysis.

Keyword(s): Magnetic Materials (1st) ; Magnetism (2nd)

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Contributing Institute(s):

1. Streumethoden (JCNS-2)
2. Streumethoden (PGI-4)
3. JARA-FIT (JARA-FIT)
4. JCNS-FRM-II (JCNS-FRM-II)

Research Program(s):

1. 144 - Controlling Collective States (POF3-144) (POF3-144)
2. 524 - Controlling Collective States (POF3-524) (POF3-524)
3. 6212 - Quantum Condensed Matter: Magnetism, Superconductivity (POF3-621) (POF3-621)
4. 6213 - Materials and Processes for Energy and Transport Technologies (POF3-621) (POF3-621)
5. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)

Experiment(s):

1. DNS: Diffuse scattering neutron time of flight spectrometer (NL6S)

Appears in the scientific report 2018

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Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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