Softening and Broadening of the Zone Boundary Magnons in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>Pr</mml:mi></mml:mrow><mml:mrow><mml:mn>0.63</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>Sr</mml:mi></mml:mrow><mml:mrow><mml:mn>0.37</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>MnO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Hwang, H. Y.; Dai, Pengcheng; Cheong, S. W.; Aeppli, G.; Tennant, A.; Mook, H. A.

doi:10.1103/physrevlett.80.1316

Cited by 129 publications

(190 citation statements)

References 23 publications

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“…Evidence of the magnon behaviour deviating from the simple nearest-neighbour Heisenberg model was first discovered in Pr 0.63 Sr 0.37 MnO 3 with T C = 301 K [24]. A clear softening of the magnon dispersion at the zone boundary for T < T C and significant broadening of the zone boundary magnons as T → T C have been observed.…”

Section: Zone-boundary Magnon Softeningmentioning

confidence: 89%

“…In the low-q limit, E(q) = + 8π 2 S(J 1 + 4J 4 )q 2 , instead of using equation (5), which takes only the nearest-neighbour coupling. It is found [21,24,28] that the contributions from the second-nearest-neighbour (J 2 ) and third-nearest-neighbour (J 2 ) exchange coupling are negligible. While the magnons show similar dispersions for R 1−x A x MnO 3 with x = 0.3 ( figure 11(a)), the doping dependence of the zone-boundary magnon softening ( figure 11(b)) indicates that the higher the doping level, the larger the zone boundary softening.…”

Section: Doping Dependence Of Magnon Excitationsmentioning

confidence: 99%

“…The solid line in figure 5 is the result of a fit to only nearest-neighbour interactions for the small-q range (ξ < 0. A Heisenberg model including higher-order couplings to fourth-neighbour interactions has been taken to fit the full data set and the results are shown in figure 5 (dashed curves) [24]. This fit gives = 0.2 ± 0.3 meV, 2J 1 S = 5.58 ± 0.07 meV, 2J 2 S = −0.36 ± 0.04 meV, 2J 3 S = 0.36 ± 0.04 meV, and 2J 4 S = 1.48 ± 0.10 meV.…”

Section: Zone-boundary Magnon Softeningmentioning

confidence: 99%

“…Right after the measurements on the magnon behaviour in FM manganites with inelastic neutron scattering, it was discovered [24,26,27] that the magnon excitation spectra have unusual large linewidths, especially near the zone boundary. As shown in figure 7, the magnon excitation peaks show a large increase of linewidth and damping when the reduced wavevector ξ > 0.3 up to the zone boundary at ξ = 0.5.…”

Section: Anomalous Magnon Dampingmentioning

confidence: 99%

“…To determine the evolution of magnon excitations in R 1−x A x MnO 3 as a function of doping, figure 11(a) summarizes the magnon dispersions along the [1, 0, 0] direction for a series of R 1−x A x MnO 3 with x ≈ 0.3 [19,21,25,27,31] while figure 11(b) presents the dispersions along the same direction but for different doping concentrations [21,24,28]. The solid curves in the figure are phenomenological fits to the data using the Heisenberg Hamiltonian equations (3) and (4) with nearest-neighbour (J 1 ) and fourth-nearest-neighbour (J 4 ) exchange coupling.…”

Section: Doping Dependence Of Magnon Excitationsmentioning

confidence: 99%

See 4 more Smart Citations

Magnons in ferromagnetic metallic manganites

Zhang¹,

Ye²,

Sha³

et al. 2007

J. Phys.: Condens. Matter

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Ferromagnetic (FM) manganites, a group of likely half-metallic oxides, are of special interest not only because they are a testing ground for the classical double-exchange interaction mechanism for the 'colossal' magnetoresistance, but also because they exhibit an extraordinary arena of emergent phenomena. These emergent phenomena are related to the complexity associated with strong interplay between charge, spin, orbital, and lattice. In this review, we focus on the use of inelastic neutron scattering to study the spin dynamics, mainly the magnon excitations in this class of FM metallic materials. In particular, we discuss the unusual magnon softening and damping near the Brillouin zone boundary in relatively narrow-band compounds with strong Jahn-Teller lattice distortion and charge-orbital correlations. The anomalous behaviours of magnons in these compounds indicate the likelihood of cooperative excitations involving spin and lattice as well as orbital degrees of freedom.

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Section: Zone-boundary Magnon Softeningmentioning

confidence: 89%

Section: Doping Dependence Of Magnon Excitationsmentioning

confidence: 99%

Section: Zone-boundary Magnon Softeningmentioning

confidence: 99%

Section: Anomalous Magnon Dampingmentioning

confidence: 99%

Section: Doping Dependence Of Magnon Excitationsmentioning

confidence: 99%

See 3 more Smart Citations

Magnons in ferromagnetic metallic manganites

Zhang¹,

Ye²,

Sha³

et al. 2007

J. Phys.: Condens. Matter

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Magnons in the Ferromagnetic Kondo-Lattice Model

Vogt

Santos

Nolting

2001

phys. stat. sol. (b)

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The magnetic properties of the ferromagnetic Kondo-lattice model (FKLM) are investigated. Starting from an analysis of the magnon spectrum in the spin-wave regime, we examine the ferromagnetic stability as a function of the occupation of the conduction band n and the strength J of the coupling between the localised moments and the conduction electrons. From the properties of the spin-wave stiffness D the ferromagnetic phase at zero temperature is derived. Using an approximate formula the critical temperature T c is calculated as a function of J and n.

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Orbital Physics in Transition Metal Oxides: Magnetism and Optics

Horsch¹

2007

Handbook of Magnetism and Advanced Magnetic Materials

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Orbital degeneracy and strong correlations in transition‐metal oxides generate spins and orbitals as low‐energy degrees of freedom. Their interplay with both real‐charge motion and virtual‐charge excitations lead to a fascinating richness of spin–charge–orbital‐ordered phases in transition‐metal oxides, to striking phenomena like the colossal magnetoresistance in manganites, the switching of charge‐ordered phases into metallic phases by applied magnetic field, and many other fascinating effects. Central topics of this review are the spin‐orbital superexchange models which provide a concise description of spin and orbital order, effective spin interactions, spin waves, and orbiton excitations in doped and undoped Mott insulators. Particular emphasis is put on recent developments of spin‐orbital superexchange models, the relation of magnetism and optical spectral weights and their temperature dependence, t 2g systems with strong composite spin‐orbital fluctuations, the concepts of orbital liquid, orbital polarons, and the colossal magnetoresistance.

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Softening and Broadening of the Zone Boundary Magnons inPr0.63Sr0.37MnO3

Cited by 129 publications

References 23 publications

Magnons in ferromagnetic metallic manganites

Magnons in ferromagnetic metallic manganites

Magnons in the Ferromagnetic Kondo-Lattice Model

Orbital Physics in Transition Metal Oxides: Magnetism and Optics

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