paper

High-field NMR study of the spin correlations in the spin-cluster mineral Na $_{2}$ Cu $_{3}$ O(SO $_{4}$ ) $_{3}$

arXiv:2306.14082 · doi:10.1103/PhysRevB.107.245134

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 $I^¼_{0} H = 7.25$ 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 $I^¼_{B}$ 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

High-field NMR study of the spin correlations in the spin-cluster mineral Na2​Cu3​O(SO4​)3​

Abstract

High-field NMR study of the spin correlations in the spin-cluster mineral Na $_{2}$ Cu $_{3}$ O(SO $_{4}$ ) $_{3}$