Local magnetic anisotropy in 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>: A polarized inelastic neutron scattering study

Qureshi, N.; Steffens, P.; Wurmehl, S.; Aswartham, Saicharan; Büchner, B.; Braden, M.

doi:10.1103/physrevb.86.060410

Cited by 63 publications

(127 citation statements)

References 40 publications

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“…In a recent polarized neutron scattering work on the AF parent compound BaFe 2 As 2 , it was found that in-plane polarized magnons exhibit a larger single iron anisotropy gap than the out-of-plane polarized ones 39 . This means that χ ′′ 110 (Q, ω) has a larger gap than χ ′′ 001 (Q, ω) at Q = (0.5, 0.5, 1) in the AF ordered state, where the Fe moments are locked to the a-axis of the orthorhombic structure [43][44][45] [along the [110] direction in our tetragonal notation].…”

Section: Discussionmentioning

confidence: 99%

Polarized neutron scattering studies of magnetic excitations in electron-overdoped superconducting BaFe1.85Ni0.15As

et al. 2012

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We use polarized inelastic neutron scattering to study low-energy spin excitations and their spatial anisotropy in electron-overdoped superconducting BaFe1.85Ni0.15As2 (Tc = 14 K). In the normal state, the imaginary part of the dynamic susceptibility, χ ′′ (Q, ω), at the antiferromagnetic (AF) wave vector Q = (0.5, 0.5, 1) increases linearly with energy for E ≤ 13 meV. Upon entering the superconducting state, a spin gap opens below E ≈ 3 meV and a broad neutron spin resonance appears at E ≈ 7 meV. Our careful neutron polarization analysis reveals that χ ′′ (Q, ω) is isotropic for the in-plane and out-of-plane components in both the normal and superconducting states. A comparison of these results with those of undoped BaFe2As2 and optimally electron-doped BaFe1.9Ni0.1As2 (Tc = 20 K) suggests that the spin anisotropy observed in BaFe1.9Ni0.1As2 is likely due to its proximity to the undoped BaFe2As2. Therefore, the neutron spin resonance is isotropic in the overdoped regime, consistent with a singlet to triplet excitation.

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Section: Discussionmentioning

confidence: 99%

Polarized neutron scattering studies of magnetic excitations in electron-overdoped superconducting BaFe1.85Ni0.15As

et al. 2012

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“…There are then six independent channels in which the instrument can be configured at a specific wave vector and energy point: three neutron polarization directions x, y, z, each of which can be measured to detect neutrons that flip or do not flip their spins when scattering at the sample. The measured neutron cross-sections are labeled by the experimental configuration in which they were measured, and are written σ SF α , σ NSF α , where α is (Qureshi et al, 2012b). Using identical experimental setup as that of (Qureshi et al, 2012b) but with much more sample mass, the energy dependence of Ma, M b , and Mc is determined at the magnetic Brillouin (e) zone center and (f) zone boundary.…”

Section: F Neutron Polarization Analysis Of Spin Excitation Anisotromentioning

confidence: 99%

“…The measured neutron cross-sections are labeled by the experimental configuration in which they were measured, and are written σ SF α , σ NSF α , where α is (Qureshi et al, 2012b). Using identical experimental setup as that of (Qureshi et al, 2012b) but with much more sample mass, the energy dependence of Ma, M b , and Mc is determined at the magnetic Brillouin (e) zone center and (f) zone boundary. The presence of longitudinal spin excitations, or nonzero Ma, is seen above 20 meV at QAF = (1, 0, 1) and above 30 meV at Q = (1, 0, 0) .…”

Section: F Neutron Polarization Analysis Of Spin Excitation Anisotromentioning

confidence: 99%

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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“…In previous polarized INS work on the parent compound BaFe 2 As 2 , spin waves below ∼12 meV are entirely c-axis polarized (M c ) [27,35]. Upon electron-doping to BaFe 2 As 2 via Co substitution to induce optimal superconductivity, polarized INS found evidence for two neutron spin resonance-like excitations with one isotropic mode (M a = M b = M c ) at an energy of ∼8 meV and a purely c-axis polarized mode (M c ) at ∼4 meV [36].…”

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confidence: 99%

Anisotropic neutron spin resonance in underdoped superconductingNaFe1−xCoxAs

et al. 2014

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We use polarized inelastic neutron scattering (INS) to study spin excitations in superconducting NaFe0.985Co0.015As (C15) with static antiferromagnetic (AF) order along the a-axis of the orthorhombic structure and NaFe0.935Co0.045As (C45) without AF order. In previous unpolarized INS work, spin excitations in C15 were found to have a dispersive sharp resonance near Er1 = 3.25 meV and a broad dispersionless mode at Er2 = 6 meV. Our neutron polarization analysis reveals that the dispersive resonance in C15 is highly anisotropic and polarized along the a-and c-axis, while the dispersionless mode is isotropic similar to that of C45. Since the a-axis polarized spin excitations of the anisotropic resonance appear below Tc, our data suggests that the itinerant electrons contributing to the magnetism are also coupled to the superconductivity.

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Local magnetic anisotropy in BaFe2As2: A polarized inelastic neutron scattering study

Cited by 63 publications

References 40 publications

Polarized neutron scattering studies of magnetic excitations in electron-overdoped superconducting BaFe1.85Ni0.15As

Polarized neutron scattering studies of magnetic excitations in electron-overdoped superconducting BaFe1.85Ni0.15As

Antiferromagnetic order and spin dynamics in iron-based superconductors

Anisotropic neutron spin resonance in underdoped superconductingNaFe1−xCoxAs

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