Magnetic order and disorder in a quasi-two-dimensional quantum Heisenberg antiferromagnet with randomized exchange

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

[img] Text
320_PhysRevB.102.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (3MB) | Request a copy
[img] Text
320_PRB_SI.pdf - Supplemental Material
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (1MB) | Request a copy

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 and 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:

30 Jun 2021 15:50

Publisher DOI:

10.1103/PhysRevB.102.174429

ArXiv ID:

2004.02547

BORIS DOI:

10.48350/153789

URI:

https://boris.unibe.ch/id/eprint/153789

Actions (login required)

Edit item Edit item
Provide Feedback