High-field NMR study of the spin correlations in the spin-cluster mineral Na${}_2$Cu${}_3$O(SO${}_4$)${}_3$

Abstract

We report NMR study on the spin correlations in the spin-cluster based mineral Na${}_2$Cu${}_3$O(SO${}_4$)${}_3$ with magnetic fields ranged from 1 T to 33 T. The long-range magnetic order is observed from both the sudden spectral broadening at $T_N$ and critical slowing down behavior in the temperature dependence of spin-lattice relaxation rates ($1/T_1(T)$). The hump behavior of $1/T_1(T)$ persists to ${\mu }_{0}H=7.25$ T, above which a spin excitation gap is observed from the thermally activated temperature dependence of $1/T_1$. The gap size shows a linear field dependence, whose slope and intercept respectively yield an effective magnetic moment of 2.54 ${\mu }_B$ and a 0.94 meV spin excitation gap under zero magnetic field. These results indicate the existence of short-range order and prominent easy-plane spin anisotropy, which are important for understanding the spin excitation spectrum in A${}_2$Cu${}_3$O(SO${}_4$)${}_3$.

5 pages, 4 figures

References in corpus (3)

• NMR studies of the incommensurate helical antiferromagnet EuCo2P2 : determination of the antiferromagnetic propagation vector
• Local evidence for collective spin excitations in the distorted kagome antiferromagnet Pr${}_3$BWO${}_9$
• Imbalanced spin couplings in the copper hexameter compounds A2Cu3O(SO4)3 (A2=Na2, NaK, K2)

Cited by in corpus (1)

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