Magnetic structure of low electron density manganites

Ohsawa, Tomokatsu; Inoue, Jun–ichiro

doi:10.1103/physrevb.65.134442

Cited by 15 publications

(5 citation statements)

References 25 publications

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“…The canting reduces with increase in J AF . Canting has also been found in the G-C boundary from a mean-field calculation [33] in the non-interacting degenerate DE model. Inclusion of J-T coupling introduces complicated phase separated regions [33] in the phase diagram.…”

Section: The Limit Of Finite J Hmentioning

confidence: 78%

“…Canting has also been found in the G-C boundary from a mean-field calculation [33] in the non-interacting degenerate DE model. Inclusion of J-T coupling introduces complicated phase separated regions [33] in the phase diagram. Experimental observations of canting in the overdoped region are rare, though a few [65] observations on Sm 1−x Ca x MnO 3 claim that the G phase, for low doping, has small canting.…”

Section: The Limit Of Finite J Hmentioning

confidence: 78%

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The overdoped colossal magnetoresistive manganites

Taraphder

2007

J. Phys.: Condens. Matter

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The rich physics in the overdoped regime in colossal magnetoresistive manganites is discussed in detail. Apart from having a large magnetoresistance like its underdoped counterpart, the overdoped regime offers a rich variety of phenomena including magnetic, charge and orbital order at low temperatures. The antiferromagnetic metallic state with anisotropic carrier transport, lowdimensional magnetic states and a broad spectrum of excitations is discussed. It is argued that the physics in the overdoped regime is primarily governed by the coupling of orbitals and spins. The Jahn-Teller effect, considered to be crucial for the understanding of underdoped manganites, does not play a major role in the overdoped region. The inadequacy of the limit of infinite Hund's coupling in describing the manganites, and the importance of Coulomb correlations, are borne out in several examples described. Bilayer manganites, owing to their layered structures, are shown to have an effectively stronger coupling with the underlying structural distortions. The charge ordering close to x = 0.5 and the effect of changing bandwidth are discussed. The effect of disorder and the possibility of having an inhomogeneous mixture of competing states are also outlined.

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Section: The Limit Of Finite J Hmentioning

confidence: 78%

Section: The Limit Of Finite J Hmentioning

confidence: 78%

The overdoped colossal magnetoresistive manganites

Taraphder

2007

J. Phys.: Condens. Matter

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“…Let us denote the canting angles at site j with j and j . The hopping between neighboring sites j and l is then given by 28,29 t → t͕cos͑ j /2͒cos͑ l /2͒ + sin͑ j /2͒sin͑ l /2͒exp͓− i͑ j − l ͔͖͒. ͑10͒…”

Section: Canting Of Localized Spinsmentioning

confidence: 99%

Phase diagram and spin-canting effects in electron-dopedLaMnO3

Schlottmann

2008

Phys. Rev. B

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In hole-doped LaMnO 3 , i.e., La is partially substituted by Ca or Sr, the manganese ions are in a mixed-valent state of two magnetic configurations, Mn 4+ ͑spin 3 / 2͒ and Mn 3+ ͑S =2͒, while in electron-doped LaMnO 3 , where La is partially replaced by Ce, the two mixed-valent configurations are Mn 3+ and Mn 2+ ͑S* =5/ 2, half-filled shell͒. The Mn 3+ configuration can be considered an e g hole in the half-filled shell. The e g holes are allowed to hop between the Mn sites with hopping amplitude t, but the multiple occupancy of the e g levels is excluded at each site by a large Coulomb energy. This hopping of the e g holes gives rise to the ferromagnetic double-exchange mechanism, which competes with the antiferromagnetic superexchange J between the localized spins S. By using a mean-field slave-boson formulation, we calculate the ground state energy of the system for the localized spins oriented in the magnetic configurations of the A, B, C, and G phases of La 1−y Ce y MnO 3 as a function of y and one model parameter, J / t. Although the models are quite different, the phase diagram for electron doping is similar to that for hole doping. The effect of canting of the spins on the band structure of the itinerant e g electrons and the stability of the A and B phases toward canting are discussed.

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“…In the DE regime (n γ = 1 for γ < m and n m = δ), which corresponds to the region ∆ 1 and J 1 in Fig. 4, the system can be described by the ferromagnetic Kondo-lattice model with an additional AFM coupling between local moments [43][44][45][46][47],…”

Section: B Split Orbitalsmentioning

confidence: 99%

Suppression and revival of long-range ferromagnetic order in the multiorbital Fermi-Hubbard model

2018

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By means of dynamical mean-field theory allowing for complete account of SU(2) rotational symmetry of interactions between spin-1/2 particles, we observe a strong effect of suppression of ferromagnetic order in the multiorbital Fermi-Hubbard model in comparison with a widely used restriction to density-density interactions. In the case of orbital degeneracy, we show that the suppression effect is the strongest in the two-orbital model (with effective spin S eff = 1) and significantly decreases when considering three orbitals (S eff = 3/2), thus magnetic ordering can effectively revive for the same range of parameters, in agreement with arguments based on vanishing of quantum fluctuations in the limit of classical spins (S eff → ∞). We analyze a connection to the double-exchange model and observe high importance of spin-flip processes there as well.arXiv:1802.02935v3 [cond-mat.str-el]

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Magnetic structure of low electron density manganites

Cited by 15 publications

References 25 publications

The overdoped colossal magnetoresistive manganites

The overdoped colossal magnetoresistive manganites

Phase diagram and spin-canting effects in electron-dopedLaMnO3

Suppression and revival of long-range ferromagnetic order in the multiorbital Fermi-Hubbard model

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