Quantum disordered ground state and relative proximity to an exactly solvable model in the frustrated magnet CeMgAl$_{11}$O$_{19}$

G. Bastien; A. Eliáš; V. Anderle; A. Kancko; C. A. Corrêa; S. Kumar; P. Proschek; J. Prokleška; L. Nádherný; D. Sedmidubský; T. Treu; P. Gegenwart; M. Kratochvílová; M. Žonda; R. H. Colman

doi:10.1103/kqxq-g723

arXiv · 2506.16207

Quantum disordered ground state and relative proximity to an exactly solvable model in the frustrated magnet CeMgAl$_{11}$O$_{19}$

G. Bastien·A. Eliáš·V. Anderle·A. Kancko·C. A. Corrêa·S. Kumar·P. Proschek·J. Prokleška·L. Nádherný·D. Sedmidubský·T. Treu·P. Gegenwart·M. Kratochvílová·M. Žonda·R. H. Colman

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Abstract

The magnetic properties of the triangular magnet CeMgAl$_{11}$O$_{19}$ were investigated by magnetization and specific heat measurements down to $T=0.03\,$K on single crystals grown by the floating zone method. The formation of effective spins $S_\mathrm{eff}= 1/2$ below $T < 10$\,K was confirmed both by DFT calculations and specific heat measurements. No magnetic order was found down to $T=0.03\,$K despite the formation of magnetic correlations observed in specific heat. The measured magnetization was compared with DMRG computation and their agreement supports the proposal of a strongly anisotropic magnetic interaction antiferromagnetically coupling the spin components in the $ab$ plane and ferromagnetically coupling the spin component along the $c$ axis. However, our quantitative study of the magnetization indicates a weaker proximity to quantum criticality between ferromagnetism and antiferromagnetism than the previous inelastic neutron scattering study. Finally, we propose that the absence of magnetic order in CeMgAl$_{11}$O$_{19}$ would most probably be related to the structural disorder revealed by single-crystal X-ray diffraction.

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G. Bastien, A. Eliáš, V. Anderle, A. Kancko, C. A. Corrêa, S. Kumar, P. Proschek, J. Prokleška, L. Nádherný, D. Sedmidubský, T. Treu, P. Gegenwart, M. Kratochvílová, M. Žonda, R. H. Colman. 2025-06-19. Quantum disordered ground state and relative proximity to an exactly solvable model in the frustrated magnet CeMgAl$_{11}$O$_{19}$. https://doi.org/10.1103/kqxq-g723

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