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Updated: Jul 30, 2025

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures
Published on: November 21, 2019
Magnetic excitations beyond the single- and double-magnons
Hebatalla Elnaggar1,2, Abhishek Nag3, Maurits W Haverkort4
1Debye Institute for Nanomaterials Science, Utrecht University, 3584 CA, Utrecht, The Netherlands. hebatalla.elnaggar@sorbonne-universite.fr.
Abstract:
A photon carrying one unit of angular momentum can change the spin angular momentum of a magnetic system with one unit (ΔMs = ±1) at most. This implies that a two-photon scattering process can manipulate the spin angular momentum of the magnetic system with a maximum of two units. Herein we describe a triple-magnon excitation in α-Fe2O3, which contradicts this conventional wisdom that only 1- and 2-magnon excitations are possible in a resonant inelastic X-ray scattering experiment. We observe an excitation at exactly three times the magnon energy, along with additional excitations at four and five times the magnon energy, suggesting quadruple and quintuple-magnons as well. Guided by theoretical calculations, we reveal how a two-photon scattering process can create exotic higher-rank magnons and the relevance of these quasiparticles for magnon-based applications.
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