Poster (Invited)

FZJ-2020-01069

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Dimerization in the commensurate antiferromagnetic phase of MnWO4 and NaFe(WO4)2

BIESENKAMP, S. ; SIDIS, Y. ; QURESHI, N. ; GORKOV, D. ; SCHMALZL, K.FZJ* ; SCHMIDT, W.FZJ* ; BECKER, P. ; BOHATÝ, L. ; BRADEN, M.

2020

Abstract: In multiferoic MnWO4, the relaxation time of the multiferroic domain inversion shows a peculiar temperature dependence. Upon cooling below the multiferroic transition the relaxation time first increases but becomes faster closer to the commensurate low-temperature phase [1]. We investigated anharmonicities in this material as well as in isostructural NaFe(WO4)2 and propose the enhanced anharmonicities close to the low-temperature magnetic up-up-down-down structure to be responsible for the faster relaxation rates in MnWO4. In both materials there is a similar competition between incommensurate cycloid and commensurate up-up-down-down order, and anharmonic squaring up appears as a precursor in the incommensurate structure [2]. The commensurate magnetic structure is associated with structural dimerization in both materials, that has been quantitatively determined for NaFe(WO4)2 by a four-circle neutron diffraction experiment. [1]: M. Baum, Phys. Rev. B 89, 144406 (2014) [2]: S. Holbein, Phys. Re. B 94, 104423 (2016)

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Contributing Institute(s):

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

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. ILL-IN12: Cold neutron 3-axis spectrometer

Appears in the scientific report 2020

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