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arXiv · 2608.29323

Experimental observation of decoupled spin subsystems in decorated square kagom\'{e} lattice magnets of the nabokoite family

V. N. Glazkov·Ya V. Rebrov·M. A. Dubovitskii·M. M. Markina·A. F. Murtazoev·P. S. Berdonosov·A. N. Vasiliev
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Abstract

The square kagom\'{e} lattice (SKL) offers a model platform for investigating geometric frustration in 2D systems. Nabokoite-family compounds \nabok{A}{X} (A=Na, K, Cs, Rb and X=Cl, Br) extend this physics to a 3D network, where 2D SKL layers are decorated by interlayer spins. Using electron paramagnetic resonance (EPR), we demonstrate a dramatic splitting of this complex exchange network into two virtually decoupled spin subsystems: absolute calibration of the electron paramagnetic resonance (EPR) absorption reveals that only a fraction of all copper spins in nabokoites is EPR-active and this fraction of the spins orders at the N\'{e}el point. Comparison of the EPR absorption and static susceptibility indicates that contribution of the EPR-silent spin subsystem to total magnetic susceptibility decreases on cooling. This direct observation of coexisting magnetic order and possible spin-liquid dynamics within a single compound challenges conventional models of unified exchange networks in decorated frustrated lattices.

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V. N. Glazkov, Ya V. Rebrov, M. A. Dubovitskii, M. M. Markina, A. F. Murtazoev, P. S. Berdonosov, A. N. Vasiliev. 2026-08-29. Experimental observation of decoupled spin subsystems in decorated square kagom\'{e} lattice magnets of the nabokoite family. https://arxiv.org/abs/2608.29323

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