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  • Letter
  • Open Access

Quantum disordered ground state and relative proximity to an exactly solvable model in the frustrated magnet CeMgAl11O19

G. Bastien1, A. Eliáš1, V. Anderle1, A. Kancko1, C. A. Corrêa2, S. Kumar1,3, P. Proschek1, J. Prokleška1, L. Nádherný4 et al.

D. Sedmidubský4, T. Treu5, P. Gegenwart5, M. Kratochvílová1, M. Žonda1, and R. H. Colman1,*

  • *Contact author: ross.colman@matfyz.cuni.cz
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Phys. Rev. Research 8, L042007 – Published 19 October, 2026

DOI: https://doi.org/10.1103/kqxq-g723

Abstract

The magnetic properties of the triangular magnet CeMgAl11O19 were investigated by magnetization and specific heat measurements down to T=0.03K on single crystals grown by the floating zone method. The formation of effective spins Seff=1/2 below T<10K was confirmed by both density functional theory calculations and specific heat measurements. No magnetic order was found down to T=0.03K despite the formation of magnetic correlations observed in specific heat. The measured magnetization was compared with density matrix renormalization group calculations 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 places CeMgAl11O19 further from the ferromagnetic quantum critical point than inferred from the previous inelastic neutron scattering study. Finally, we suggest that the absence of magnetic order may be promoted by the structural disorder revealed by single-crystal x-ray diffraction [Ce deficiency, Mg/Al site mixing, and Al(5) splitting].

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Phys. Rev. Research 8, L042007– Published 19 October, 2026
  • Received 16 June 2025
  • Accepted 19 August 2026
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