High-frequency dielectric anomalies in a highly frustrated square kagome lattice nabokoite family compounds ACu${}_7$(TeO${}_4$)(SO${}_4$)${}_5$Cl (A=Na, K, Rb, Cs)

Abstract

Nabokoite family compounds ACu${}_7$(TeO${}_4$)(SO${}_4$)${}_5$Cl (A=Na, K, Cs, Rb) are candidates for the experimental realization of highly-frustrated 2D square kagome lattice (SKL). Their magnetic subsystem includes SKL layers decorated by additional copper ions. All members of this family are characterized by quite high Curie-Weiss temperatures ($\sim 80-200$ K), but magnetic ordering was reported only for Na and K compounds at a much lower temperatures below 4 K. We report here results of the study of high-frequency ($\sim 10$ GHz) dielectric properties of this family of compounds. Our study revealed presence of the strong dielectric anomaly both in the real and imaginary parts of high-frequency dielectric permittivity for Na and K compounds approx. 100 and 26 K, correspondingly, presumably related to antiferroelectric ordering. Additionally, much weaker anomalies were observed at approximately 5K indicating possible interplay of magnetic and lattice degrees of freedom. We discuss possible relation between the structure rearrangements accompanying dielectric anomalies and a delayed magnetic ordering in the nabokoite family compounds.

arXiv comment12 pages, 8 figures

References in corpus (13)

• Anyons in an exactly solved model and beyond
• Gapless spin-liquid ground state in the $S=1/2$ kagome antiferromagnet
• 17O NMR study of the intrinsic magnetic susceptibility and spin dynamics of the quantum kagome antiferromagnet ZnCu3(OH)6Cl2
• Gapped spin liquid with ${\mathbb{Z}}_2$-topological order for kagome Heisenberg model
• The $S=1/2$ Kagome Heisenberg Antiferromagnet Revisited
• The "Square Kagome" Quantum Antiferromagnet and the Eight Vertex Model
• Emergence of spin singlets with inhomogeneous gaps in the kagome Heisenberg antiferromagnets Zn-barlowite and herbertsmithite
• Frustrated magnetism and resonating valence bond physics in two-dimensional kagome-like magnets
• Fragmentation in Frustrated Magnets -- A review
• Topological Nematic Spin Liquid on the Square-Kagome Lattice
• Thermodynamics of the spin-half square-kagome lattice antiferromagnet
• Magnetic phase diagrams and magnetization plateaus of the spin-1/2 antiferromagnetic Heisenberg model on square-kagome lattice with three nonequivalent exchange interactions
• Magnetism of the $s=1/2$ $J_1$-$J_2$ square-kagome lattice antiferromagnet

Cited by in corpus (1)

• Quantum phase diagram of the spin-$\frac{1}{2}$ Heisenberg antiferromagnet on the square-kagome lattice: a tensor network study