Xiao, F.; Blackmore, W. J. A.; Huddart, B. M.; Gomilšek, M.; Hicken, T. J.; Baines, C.; Baker, P. J.; Pratt, F. L.; Blundell, S. J.; Lu, H.; Singleton, J.; Gawryluk, D.; Turnbull, M. M.; Krämer, Karl; Goddard, P. A.; Lancaster, T. (2020). Magnetic order and disorder in a quasi-two-dimensional quantum Heisenberg antiferromagnet with randomized exchange. Physical Review B, 102(17), p. 174429. American Physical Society APS 10.1103/PhysRevB.102.174429
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We present an investigation of the effect of randomizing exchange coupling strengths in the S=1/2 square lattice quasi-two-dimensional quantum Heisenberg antiferromagnet (QHAF) (QuinH)2Cu(ClxBr1−x)4⋅2H2O (QuinH = Quinolinium, C9H8N+), with 0≤x≤1. Pulsed-field magnetization measurements allow us to estimate an effective in-plane exchange strength J in a regime where exchange fosters short-range order, while the temperature TN at which long-range order (LRO) occurs is found using muon-spin relaxation, allowing us to construct a phase diagram for the series. We evaluate the effectiveness of disorder in suppressing TN and the ordered moment size, and we find an extended disordered phase in the region 0.4≲x≲0.8 where no magnetic order occurs. The observed critical substitution levels are accounted for by an energetics-based competition between different local magnetic orders. Furthermore, we demonstrate experimentally that the ground-state disorder is driven by quantum effects of the exchange randomness, which is a feature that has been predicted theoretically and has implications for other disordered quasi-two-dimensional QHAFs.
Item Type: |
Journal Article (Original Article) |
|---|---|
Division/Institute: |
08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP) |
UniBE Contributor: |
Xiao, Fan, Krämer, Karl |
Subjects: |
500 Science > 570 Life sciences; biology 500 Science > 540 Chemistry 500 Science > 530 Physics |
ISSN: |
2469-9950 |
Publisher: |
American Physical Society APS |
Language: |
English |
Submitter: |
Karl Krämer |
Date Deposited: |
01 Apr 2021 17:20 |
Last Modified: |
05 Dec 2022 15:49 |
Publisher DOI: |
10.1103/PhysRevB.102.174429 |
ArXiv ID: |
2004.02547 |
BORIS DOI: |
10.48350/153789 |
URI: |
https://boris.unibe.ch/id/eprint/153789 |
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