From one- to two-magnon excitations in the S=3/2 magnet $\beta$-CaCr${}_2$O${}_4$

Abstract

We apply neutron spectroscopy to measure the magnetic dynamics in the S=3/2 magnet $\beta$-CaCr${}_2$O${}_4$ (T${}_N$=21 K). The low-energy fluctuations, in the ordered state, resemble large-S linear spin-waves from the incommensurate ground state. However, at higher energy transfers, these semi-classical and harmonic dynamics are replaced by an energy and momentum broadened continuum of excitations. Applying kinematic constraints required for energy and momentum conservation, sum rules of neutron scattering, and comparison against exact diagonalization calculations, we show that the dynamics at high-energy transfers resemble low-S one-dimensional quantum fluctuations. $\beta$-CaCr${}_2$O${}_4$ represents an example of a magnet at the border between classical Néel and quantum phases, displaying dual characteristics.

References in corpus (28)

• Dynamics of coupled quantum spin chains
• Fractional spinon excitations in the quantum Heisenberg antiferromagnetic chain
• Spin-waves in triangular lattice antiferromagnet: decays, spectrum renormalization, and singularities
• Multispinon continua at zero and finite temperature in a near-ideal Heisenberg chain
• Confinement of fractional quantum number particles in a condensed matter system
• Extended quantum critical phase in a magnetized spin-1/2 antiferromagnetic chain
• Dynamical structure factor of triangular-lattice antiferromagnet
• Magnon Decay in Noncollinear Quantum Antiferromagnets
• Quasi-1D spin-1/2 Heisenberg magnets in their ordered phase: correlation functions
• Absolute cross-section normalization of magnetic neutron scattering data
• Bound spinons in an antiferromagnetic S=1/2 chain with a staggered field
• Non-collinear spin-density wave antiferromagnetism in FeAs
• Two-magnon excitations observed by neutron scattering in the two-dimensional spin-5/2 Heisenberg antiferromagnet Rb2MnF4
• Zig-zag ladders with staggered magnetic chirality in S = 3/2 compound beta-CaCr2O4
• Incommensurate short-range order in the S=1 triangular antiferromagnet NiGa2S4
• Spin Reduction Transition in Spin-3/2 Random Heisenberg Chains
• Longitudinal Magnetic Dynamics and Dimensional Crossover in the Quasi-One-Dimensional, Spin-1/2, Heisenberg Antiferromagnet KCuF3
• Soft striped magnetic fluctuations competing with superconductivity in Fe_{1+x}Te
• Dominance of excitation continuum in the longitudinal spectrum of weakly coupled Heisenberg S=1/2 chains
• Solitary magnons in the $S=\frac{5}{2}$ antiferromagnet CaFe${}_2$O${}_4$
• Single to multi quasiparticle excitations in the itinerant helical magnet CeRhIn${}_5$
• Polarization dependence of spin excitations in BaCu2Si2O7
• Decay of spin-spin correlations in disordered quantum and classical spin chains
• Ordered magnetism in the intrinsically decorated $j{}_{\mathrm{eff}}$ = $\frac{1}{2}$ $\alpha$-CoV${}_3$O${}_8$
• Anharmonic magnon excitations in noncollinear and charge-ordered RbFe${}^{2+}$Fe${}^{3+}$F${}_6$
• Orphan spins and bound in-gap states in the $S=\frac{5}{2}$ antiferromagnet CaFe${}_2$O${}_4$
• From mean-field localized magnetism to itinerant spin fluctuations in the "Non-metallic metal" - FeCrAs
• Imitation of spin density wave order in Cu${}_3$Nb${}_2$O${}_8$

Cited by in corpus (8)

• Frustration model and spin excitations in the helimagnet FeP
• Metastable antiphase boundary ordering in CaFe${}_2$O${}_4$
• Strain-induced phase diagram of the $S=\frac{3}{2}$ Kitaev material $\mathrm{CrSiT}{\mathrm{e}}_3$
• Kernel Polynomial Method for Linear Spin Wave Theory
• Excitonic transverse and amplitude fluctuations in the noncollinear and charge-ordered RbFe${}^{2+}$Fe${}^{3+}$F${}_6$
• Neutron scattering sum rules, symmetric exchanges, and helicoidal magnetism in MnSb${}_2$O${}_6$
• Spin and lattice dynamics of a van der Waals antiferromagnet MnPSe${}_3$
• Single-ion anisotropy driven chiral magnetic order in a spin-1 antiferromagnetic chain