Journal Article

FZJ-2020-00155

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Partial Up-Up-Down Order with the Continuously Distributed Order Parameter in the Triangular Antiferromagnet TmMgGaO 4

Li, Y. (Corresponding author) ; Bachus, S. ; Deng, H. ; Schmidt, W.FZJ* ; Thoma, H.FZJ* ; Hutanu, V.FZJ* ; Tokiwa, Y. ; Tsirlin, A. A. ; Gegenwart, P.

2020
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/23843  doi:10.1103/PhysRevX.10.011007

Abstract: We show that frustrated quasidoublets without time-reversal symmetry can host highly unconventional magnetic structures with continuously distributed order parameters even in a single-phase crystal. Our study comprises a comprehensive thermodynamic and neutron diffraction investigation on the single crystal of TmMgGaO4, which entails non-Kramers Tm3+ ions arranged on a geometrically perfect triangular lattice. The crystal electric field randomness caused by the site-mixing disorder of the nonmagnetic Mg2+ and Ga3+ ions merges two lowest-lying crystal electric field singlets of Tm3+ into a ground-state quasidoublet. Well below Tc∼0.7  K, a small fraction of the antiferromagnetically coupled Tm3+ Ising quasidoublets with small inner gaps condense into two-dimensional up-up-down magnetic structures with continuously distributed order parameters, and give rise to the columnar magnetic neutron reflections below μ0Hc∼2.6  T, with highly anisotropic correlation lengths, ξab≥250a in the triangular plane and ξc<c/12 between the planes. The remaining fraction of the Tm3+ ions remain nonmagnetic at 0 T and become uniformly polarized by the applied longitudinal field at low temperatures. We argue that the similar model can be generally applied to other compounds of non-Kramers rare-earth ions with correlated ground-state quasidoublets.

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

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS-FRM-II)
2. Streumethoden (JCNS-2)
3. JCNS-ILL (JCNS-ILL)
4. Heinz Maier-Leibnitz Zentrum (MLZ)
5. Streumethoden (PGI-4)
6. JARA-FIT (JARA-FIT)

Research Program(s):

1. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)
3. 144 - Controlling Collective States (POF3-144) (POF3-144)
4. 6212 - Quantum Condensed Matter: Magnetism, Superconductivity (POF3-621) (POF3-621)
5. 6213 - Materials and Processes for Energy and Transport Technologies (POF3-621) (POF3-621)
6. 524 - Controlling Collective States (POF3-524) (POF3-524)

Experiment(s):

1. POLI: Polarized hot neutron diffractometer (SR9a)

Appears in the scientific report 2020

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Database coverage:
; ; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; IF >= 10 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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