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Supercooling and fragile glassiness in a dipolar kagome Ising magnet

Accepted version
Peer-reviewed

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Type

Article

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Authors

Hamp, J 
Moessner, R 
Castelnovo, Claudio  ORCID logo  https://orcid.org/0000-0003-1752-6343

Abstract

We study equilibration and ordering in the classical dipolar kagome Ising antiferromagnet, which we show behaves as a disorder-free fragile spin glass. By identifying an appropriate order parameter, we demonstrate a transition to the ordered state proposed by Chioar et al. [Phys. Rev. B 93, 214410 (2016)] with a 12-site unit cell that breaks time-reversal and sublattice symmetries, and further provide evidence that the nature of the transition is first order. Upon approaching the transition, the spin dynamics slow dramatically. The system readily falls out of equilibrium, overshooting the transition and entering a supercooled liquid regime. Using extensive Monte Carlo simulations, we show that the system exhibits super-Arrhenius behaviour above the ordering transition. The relaxation time diverges according to a Vogel-Fulcher form at a finite `glass transition' temperature in the supercooled regime. Such behaviour, characteristic of fragile glasses, is particularly remarkable as the model is free of quenched disorder, does not straightforwardly conform to the avoided criticality paradigm, and is simple and eminently realisable in engineered nanomagnetic arrays.

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Keywords

cond-mat.str-el, cond-mat.str-el, cond-mat.dis-nn, cond-mat.stat-mech

Journal Title

Physical Review B

Conference Name

Journal ISSN

2469-9950
2469-9969

Volume Title

98

Publisher

American Physical Society (APS)
Sponsorship
Engineering and Physical Sciences Research Council (EP/K028960/1)
Engineering and Physical Sciences Research Council (EP/P034616/1)
Engineering and Physical Sciences Research Council (EP/M007065/1)