Competition between stripe and checkerboard magnetic instabilities in Mn-doped BaFe<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>As<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>

Tucker, G. S.; Pratt, Dan E.; Kim, M. G.; Ran, Sheng; Thaler, A.; Granroth, G. E.; Marty, Karol; Wang, Tian; Zarestky, J.; Lumsden, M. D.; Bud’ko, Sergey L.; Canfield, Paul C.; Kreyßig, A.; Goldman, A. I.; McQueeney, R. J.

doi:10.1103/physrevb.86.020503

Cited by 51 publications

(70 citation statements)

References 27 publications

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“…Figure 26(a) shows spin excitations of the system measured with the crystallographic c axis parallel to the incident neutron beam at E i = 74.8 meV. In addition to spin excitations associated with the collinear AF structure denoted as Q stripe = Q AF , there are excitations at the AF wave vector positions of BaMn 2 As 2 (Q Néel ) (Tucker et al, 2012b). At present, it is unclear if this is an intrinsic effect of the system or there is real space phase separation between Mn and Fe.…”

Section: Evolution Of Spin Excitations In Iron Chalcogenides and Amentioning

confidence: 99%

“…On the other hand, Mn-doped BaFe 2 As 2 represents a more complicated situation: while BaMn 2 As 2 forms a simple AF structure with the ordered moment along the c axis (Singh et al, 2009), Mn-doping of BaFe 2 As 2 may induce a Griffiths regime associated with the suppression of the collinear AF order in BaFe 2 As 2 by the randomly introduced localized Mn moments acting as strong mag- netic impurities (Inosov et al, 2013). Inelastic neutron scattering experiments were carried out on single crystals of Ba(Fe 1−x Mn x ) 2 As 2 with x = 0.075, which has a tetragonal-to-orthorhombic lattice distortion and orders into a collinear AF structure simultaneously below T s = T N = 80 K (Tucker et al, 2012b). Figure 26(a) shows spin excitations of the system measured with the crystallographic c axis parallel to the incident neutron beam at E i = 74.8 meV.…”

Section: Evolution Of Spin Excitations In Iron Chalcogenides and Amentioning

confidence: 99%

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Antiferromagnetic order and spin dynamics in iron-based superconductors

2015

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High-transition temperature (high-Tc) superconductivity in the iron pnictides/chalcogenides emerges from the suppression of the static antiferromagnetic order in their parent compounds, similar to copper oxides superconductors. This raises a fundamental question concerning the role of magnetism in the superconductivity of these materials. Neutron scattering, a powerful probe to study the magnetic order and spin dynamics, plays an essential role in determining the relationship between magnetism and superconductivity in high-Tc superconductors. The rapid development of modern neutron time-of-flight spectrometers allows a direct determination of the spin dynamical properties of iron-based superconductors throughout the entire Brillouin zone. In this review, we present an overview of the neutron scattering results on iron-based superconductors, focusing on the evolution of spin excitation spectra as a function of electron/hole-doping and isoelectronic substitution. We compare spin dynamical properties of iron-based superconductors with those of copper oxide and heavy fermion superconductors, and discuss the common features of spin excitations in these three families of unconventional superconductors and their relationship with superconductivity.

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Section: Evolution Of Spin Excitations In Iron Chalcogenides and Amentioning

confidence: 99%

Section: Evolution Of Spin Excitations In Iron Chalcogenides and Amentioning

confidence: 99%

Antiferromagnetic order and spin dynamics in iron-based superconductors

2015

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“…Neutron and X-ray diffraction measurements on Ba(Fe 1−x Mn x ) 2 As 2 reported the suppression of the orthorhombic to tetragonal structural transition at x ∼ 0.1 but that the Bragg peaks corresponding to stripe order [(π, 0) or (0, π)] survive in the tetragonal lattice for x > 0.1 [288]. Inelastic neutron scattering experiments [289] reported the coexistence of both (π, 0) and (π, π) spin fluctuations for Ba(Fe 0.925 Mn 0.075 ) 2 As 2 . Fluctuations at (π, 0) have a strong temperature dependence with its signal becoming broader above T N .…”

Section: B Magnetic Softness In Doped Compoundsmentioning

confidence: 99%

Magnetic interactions in iron superconductors: A review

Bascones

Valenzuela

Calderón

2015

Comptes Rendus. Physique

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High temperature superconductivity in iron pnictides and chalcogenides emerges when a magnetic phase is suppressed. The multi-orbital character and the strength of correlations underlie this complex phenomenology, involving magnetic softness and anisotropies, with Hund's coupling playing an important role. We review here the different theoretical approaches used to describe the magnetic interactions in these systems. We show that taking into account the orbital degree of freedom allows us to unify in a single phase diagram the main mechanisms proposed to explain the (π, 0) order in iron pnictides: the nesting-driven, the exchange between localized spins, and the Hund induced magnetic state with orbital differentiation. Comparison of theoretical estimates and experimental results helps locate the Fe superconductors in the phase diagram. In addition, orbital physics is crucial to address the magnetic softness, the doping dependent properties, and the anisotropies.

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“…In addition, inelastic neutron scattering revealed that Mn dopants induce short-range quasi-elastic spin scattering at (π, π) ≡ Q Néel , which persists at all measured T , and coexists with the long-range ordered Q stripe phase at low T . [14] The presence of local antiferromagnetic (AF) correlations induced by Mn ions have also been detected by nuclear magnetic resonance (NMR). [23,24] These studies therefore suggest that Mn locally nucleate magnetic moments consistent with Q Néel structure.…”

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confidence: 99%

“…The impurity nucleates a checkerboard polarization which is weakly T -dependent and persists well beyond T N consistent with µSR, [15] NMR, [23] and neutron scattering. [14].…”

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confidence: 99%

Enhancement of Magnetic Stripe Order in Iron-Pnictide Superconductors from the Interaction between Conduction Electrons and Magnetic Impurities

Gastiasoro

Andersen

2014

Phys. Rev. Lett.

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Recent experimental studies have revealed several unexpected properties of Mn-doped BaFe2As2. These include extension of the stripe-like magnetic (π, 0) phase to high temperatures above a critical Mn concentration only, the presence of diffusive and weakly temperature dependent magnetic (π, π) checkerboard scattering, and an apparent absent structural distortion from tetragonal to orthorhombic. Here, we study the effects of magnetic impurities both below and above the Néel transition temperature within a real-space five-band model appropriate to the iron pnictides. We show how these experimental findings can be explained by a cooperative behavior of the magnetic impurities and the conduction electrons mediating the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between them.PACS numbers: 74.62. En, 74.70.Xa, 75.30.Hx Whether the electronic fluctuations in Fe-based superconductors are predominantly of magnetic or orbital nature remains controversial.[1] The structural transition from tetragonal to orthorhombic symmetry has been argued to arise from an electronically driven nematic instability caused either by orbital order [2][3][4][5] or so-called spin-Ising order.[6-9] These order parameters are, however, intimately linked by symmetry and cannot exist on their own,[1] making it hard to determine experimentally which order exhibits the dominant susceptibility in the high-T normal phase and hence drive e.g. the structural transition. A resolution to this question is of great interest since the dominant fluctuations are likely to also mediate the pairing required for superconductivity. Therefore, the presence of a magnetic tetragonal phase has attracted a lot of attention [10,11]; this phase exhibits magnetic order at the same ordering vectors (π, 0), (0, π) ≡ Q stripe as the standard stripe magnetic order, but without a concomitant breaking the tetragonal symmetry. The existence of magnetic non-orthorhombic phases argues against orbital order as the driving instability of these materials, and has been interpreted in terms of C 4 symmetric magnetic structures with ordering at Q stripe . [12,13] For the pnictides, the above issues have largely focussed on hole-doped BaFe 2 As 2 where particularly Ba(Fe 1−x Mn x ) 2 As 2 constitutes an interesting case in point. For this compound, Kim et al. [10] found that the structural phase transition disappears at a critical Mn doping (x c ∼ 0.1) whereas the Q stripe magnetic order remains. Remarkably, at higher doping than x c the magnetic order exhibits a new high-temperature component as seen by the persistence of a broad Q stripe magnetic Bragg peak well in excess of the Néel temperature T N of the lower doped x < x c samples. In addition, inelastic neutron scattering revealed that Mn dopants induce short-range quasi-elastic spin scattering at (π, π) ≡ Q Néel , which persists at all measured T , and coexists with the long-range ordered Q stripe phase at low T .[14] The presence of local antiferromagnetic (AF) correlations induced by Mn ions have also been detected by ...

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Competition between stripe and checkerboard magnetic instabilities in Mn-doped BaFe2As2

Cited by 51 publications

References 27 publications

Antiferromagnetic order and spin dynamics in iron-based superconductors

Antiferromagnetic order and spin dynamics in iron-based superconductors

Magnetic interactions in iron superconductors: A review

Enhancement of Magnetic Stripe Order in Iron-Pnictide Superconductors from the Interaction between Conduction Electrons and Magnetic Impurities

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