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Dynamical moment fragmentation in the all-in all-out pyrochlore Nd2Sn2O7

Yi Luo1,*, Matthew S. Powell2, Joseph A. M. Paddison1, Brenden R. Ortiz3, J. Ross Stewart4, Joseph W. Kolis2, and Adam A. Aczel1,†

  • *Contact author: luoy1@ornl.gov
  • †Contact author: aczelaa@ornl.gov
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Phys. Rev. B 113, L180402 – Published 4 May, 2026

DOI: https://doi.org/10.1103/ts2j-thc8

Abstract

We report single-crystal neutron spectroscopy and bulk characterization of hydrothermally grown Nd2Sn2O7, revealing a dynamical moment fragmentation embedded within the all-in all-out ordered state. The spectra show a nearly flat band with pinch-point-like momentum dependence, accompanied by dispersive branches that generate half-moon features across multiple Brillouin zones. These defining signatures are captured quantitatively by a minimal dipolar-octupolar spin Hamiltonian, demonstrating excellent agreement between experiment and theory. The higher flat-mode energy helps account for the absence of dynamical interference in prior muon spin relaxation µSR studies, while the lack of any photonlike excitation imposes strict constraints on the proposed Coulombic antiferromagnet scenario. Our results extend dynamical moment fragmentation to Nd2Sn2O7 and identify it as a clean, tractable platform for quantitative exploration of emergent gauge-field physics and multipolar spin-wave dynamics in frustrated magnets.

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Outline

Information

Phys. Rev. B 113, L180402– Published 4 May, 2026
  • Received 7 October 2025
  • Revised 2 March 2026
  • Accepted 12 March 2026
Article part of CHORUS
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