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arXiv · 1605.04199

Spiral spin-liquid and the emergence of a vortex-like state in MnSc$_2$S$_4$

Shang Gao·Oksana Zaharko·Vladmir Tsurkan·Yixi Su·Jonathan S. White·Gregory S. Tucker·Bertrand Roessli·Frederic Bourdarot·Romain Sibille·Dmitry Chernyshov·Tom Fennell·Alois Loidl·Christian Rüegg
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Abstract

Spirals and helices are common motifs of long-range order in magnetic solids, and they may also be organized into more complex emergent structures such as magnetic skyrmions and vortices. A new type of spiral state, the spiral spin-liquid, in which spins fluctuate collectively as spirals, has recently been predicted to exist. Here, using neutron scattering techniques, we experimentally prove the existence of a spiral spin-liquid in MnSc$_2$S$_4$ by directly observing the 'spiral surface' - a continuous surface of spiral propagation vectors in reciprocal space. We elucidate the multi-step ordering behavior of the spiral spin-liquid, and discover a vortex-like triple-q phase on application of a magnetic field. Our results prove the effectiveness of the $J_1$-$J_2$ Hamiltonian on the diamond lattice as a model for the spiral spin-liquid state in MnSc$_2$S$_4$, and also demonstrate a new way to realize a magnetic vortex lattice.

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Shang Gao, Oksana Zaharko, Vladmir Tsurkan, Yixi Su, Jonathan S. White, Gregory S. Tucker, Bertrand Roessli, Frederic Bourdarot, Romain Sibille, Dmitry Chernyshov, Tom Fennell, Alois Loidl, Christian Rüegg. 2016-05-13. Spiral spin-liquid and the emergence of a vortex-like state in MnSc$_2$S$_4$. https://doi.org/10.1038/nphys3914

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