Spin-Wave Dispersion in Orbitally Ordered<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>La</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi>Sr</mml:mi><mml:mrow><mml:mn>3</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mi>MnO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>

Senff, D.; Krüger, Frank; Scheidl, Stefan; Benomar, M.; Sidis, Y.; Demmel, F.; Braden, M.

doi:10.1103/physrevlett.96.257201

Cited by 37 publications

(74 citation statements)

References 31 publications

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“…We determined from our global best fit that J F 1 = 9.01 ± 0.02 meV. This value is comparable to that measured in PCSMO (11.39 ± 0.05 meV) 39 , La 0.5 Sr 1.5 MnO 4 (9.98 meV) 41 , the AFM CO phases of Nd 0.5 Sr 0.5 MnO 3 (6.76 meV) 42 , and a little larger than the typical values for the FM double exchange in metallic FM manganites 37,59 . In other words, it is consistent with its origin being due to double exchange.…”

Section: A Goodenough Modelsupporting

confidence: 69%

“…However, calculation of the excitation spectra within such a framework is, though possible, far from straightforward 49,50 . In the absence of such calculations, we therefore use an effective Heisenberg Hamiltonian to model our data, just as was done for the half-doped manganites mentioned in the introduction 39,41,42 .The use of an effective Heisenberg Hamiltonian is a well-established procedure to analyze the spin wave spectra in magnetically ordered systems, and not just those with purely integer or halfinteger spins, nor even solely insulators. The exchange interactions in the model Hamiltonian that are required to reproduce the observed dispersion relations and intensities establish the strength, range and symmetries of the magnetic interactions.…”

Section: Discussionmentioning

confidence: 99%

“…1(a), since this then provides a natural explanation of how the signs of the nearest neighbor exchange interactions we consider come about. We also allow for the possibility of next-nearestneighbor interactions along the FM zig-zags, as has been required in previous studies of similar systems 39,41,42 and is taken to indicate a degree of electronic itinerancy along the zig-zag chains.…”

Section: A Goodenough Modelmentioning

confidence: 99%

“…As discussed briefly above, in two earlier studies of the spin waves in CE-type half-doped manganites 41,42 , single-layered La 1/2 Sr 3/2 MnO 4 and pseudo-cubic Nd 0.5 Sr 0.5 MnO 3 , the lower part of the spin wave dispersion was measured and found to be well-explained by the Goodenough model including second neighbor exchange J F 2 along the FM zig-zags (see Fig. 1(a)).…”

Section: Introductionmentioning

confidence: 99%

“…First is the question of whether or not the Mn ions are paired in a dimer-like fashion in Pr 0.5 Ca 0.5 MnO 3 . On the basis of previous inelastic neutron scattering measurements of other half-doped manganites 39,41,42 we might expect the Goodenough model to provide a better description than models involving dimerization. However, since Pr 1−x Ca x MnO 3 is the material in which the possible existence of Zener polarons came to prominence, we believe that it is important to confirm whether or not this is the case.…”

Section: Introductionmentioning

confidence: 99%

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Spin excitations used to probe the nature of exchange coupling in the magnetically ordered ground state ofPr0.5Ca0.5MnO3

et al. 2016

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Spin excitations used to probe the nature of the exchange coupling in the magnetically ordered ground state of Pr 0.5 Ca 0. We have used time-of-flight inelastic neutron scattering to measure the spin wave spectrum of the canonical half-doped manganite Pr0.5Ca0.5MnO3 in its magnetic and orbitally ordered phase. The data, which cover multiple Brillouin zones and the entire energy range of the excitations, are compared with several different models that are all consistent with the CE-type magnetic order, but arise through different exchange coupling schemes. The Goodenough model, i.e. an ordered state comprising strong nearest neighbor ferromagnetic interactions along zig-zag chains with antiferromagnetic inter-chain coupling, provides the best description of the data, provided that further neighbor interactions along the chains are included. We are able to rule out a coupling scheme involving formation of strongly bound ferromagnetic dimers, i.e. Zener polarons, on the basis of gross features of the observed spin wave spectrum. A model with weaker dimerization reproduces the observed dispersion but can be ruled out on the basis of discrepancies between the calculated and observed structure factors at certain positions in reciprocal space. Adding further neighbor interactions results in almost no dimerization, i.e. recovery of the Goodenough model. These results are consistent with theoretical analysis of the degenerate double exchange model for half-doping, and provide a recipe for how to interpret future measurements away from half-doping, where degenerate double exchange models predict more complex ground states.

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Section: A Goodenough Modelsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Section: A Goodenough Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Spin excitations used to probe the nature of exchange coupling in the magnetically ordered ground state ofPr0.5Ca0.5MnO3

et al. 2016

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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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Spin Excitations in Half-Doped Manganites

Buitrago

Ventura

2012

J Supercond Nov Magn

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We investigate magnetic excitations in half-doped colossal magnetoresistance manganites. In particular, we focus on spin excitations in the CE phase originally proposed by Goodenough (Phys. Rev. 100, 564 (1955)). Using a localized spin model we calculated magnons for 3D-perovskite compounds such as La$_{1-x}$M$_x$MnO$_3$, where M=Ca,Sr,Ba, and for their 2D-laminar counterparts. We compared them with predictions for the spin excitations corresponding to other phases proposed. For the laminar half-doped manganite La$_{0.5}$Sr$_{1.5}$MnO$_4$, for which magnon measurements by inelastic neutron scattering exist, as well as an estimation of the magnetic couplings, our calculations agree well with the experimental data.Comment: 3 pages, 4 figures Manuscript accepted: Nov.2011 Published online: 3 Jan. 201

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Spin-Wave Dispersion in Orbitally OrderedLa1/2Sr3/2MnO4

Cited by 37 publications

References 31 publications

Spin excitations used to probe the nature of exchange coupling in the magnetically ordered ground state ofPr0.5Ca0.5MnO3

Spin excitations used to probe the nature of exchange coupling in the magnetically ordered ground state ofPr0.5Ca0.5MnO3

Orbital Physics in Transition Metal Oxides: Magnetism and Optics

Spin Excitations in Half-Doped Manganites

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