scholarly journals Nematic spin correlations in the tetragonal state of uniaxial-strained BaFe2−xNixAs2

Science ◽  
2014 ◽  
Vol 345 (6197) ◽  
pp. 657-660 ◽  
Author(s):  
Xingye Lu ◽  
J. T. Park ◽  
Rui Zhang ◽  
Huiqian Luo ◽  
Andriy H. Nevidomskyy ◽  
...  
Keyword(s):  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Low Energy ◽  
Iron Pnictides ◽  
Spin Excitation ◽  
Spin Correlations ◽  
Spin Excitations ◽  
Resistivity Anisotropy ◽  
High Transition ◽  
Mechanism Of Superconductivity

Understanding the microscopic origins of electronic phases in high-transition temperature (high-Tc) superconductors is important for elucidating the mechanism of superconductivity. In the paramagnetic tetragonal phase of BaFe2−xTxAs2 (where T is Co or Ni) iron pnictides, an in-plane resistivity anisotropy has been observed. Here, we use inelastic neutron scattering to show that low-energy spin excitations in these materials change from fourfold symmetric to twofold symmetric at temperatures corresponding to the onset of the in-plane resistivity anisotropy. Because resistivity and spin excitation anisotropies both vanish near optimal superconductivity, we conclude that they are likely intimately connected.

scholarly journals Low-energy spin excitations in (Li0.8Fe0.2)ODFeSe superconductor studied with inelastic neutron scattering

2017 ◽  
Vol 95 (10) ◽  
Author(s):  
Mingwei Ma ◽  
Lichen Wang ◽  
Philippe Bourges ◽  
Yvan Sidis ◽  
Sergey Danilkin ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Low Energy ◽  
Spin Excitations

scholarly journals Spin excitations in metallic kagome lattice FeSn and CoSn

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yaofeng Xie ◽  
Lebing Chen ◽  
Tong Chen ◽  
Qi Wang ◽  
Qiangwei Yin ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Spin Waves ◽  
Inelastic Neutron ◽  
Spin Excitation ◽  
Destructive Interference ◽  
Kagome Lattice ◽  
Kagomé Lattice ◽  
Flat Bands ◽  
Spin Excitations

AbstractIn two-dimensional (2D) metallic kagome lattice materials, destructive interference of electronic hopping pathways around the kagome bracket can produce nearly localized electrons, and thus electronic bands that are flat in momentum space. When ferromagnetic order breaks the degeneracy of the electronic bands and splits them into the spin-up majority and spin-down minority electronic bands, quasiparticle excitations between the spin-up and spin-down flat bands should form a narrow localized spin-excitation Stoner continuum coexisting with well-defined spin waves in the long wavelengths. Here we report inelastic neutron scattering studies of spin excitations in 2D metallic kagome lattice antiferromagnetic FeSn and paramagnetic CoSn, where angle resolved photoemission spectroscopy experiments found spin-polarized and nonpolarized flat bands, respectively, below the Fermi level. Our measurements on FeSn and CoSn reveal well-defined spin waves extending above 140 meV and correlated paramagnetic scattering around Γ point below 90 meV, respectively. In addition, we observed non-dispersive excitations at ~170 meV and ~360 meV arising mostly from hydrocarbon scattering of the CYTOP-M used to glue the samples to aluminum holder. Therefore, our results established the evolution of spin excitations in FeSn and CoSn, and identified anomalous flat modes overlooked by the neutron scattering community for many years.

scholarly journals Spin excitations in metallic kagome lattice FeSn and CoSn

2021 ◽  
Author(s):  
Yaofeng Xie ◽  
Lebing Chen ◽  
Tong Chen ◽  
Qi Wang ◽  
Qiangwei Yin ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Spin Waves ◽  
Inelastic Neutron ◽  
Spin Excitation ◽  
Destructive Interference ◽  
Kagome Lattice ◽  
Kagomé Lattice ◽  
Flat Bands ◽  
Spin Excitations

Abstract In two-dimensional (2D) metallic kagome lattice materials, destructive interference of electronic hopping pathways around the kagome bracket can produce nearly localized electrons, and thus electronic bands that are flat in momentum space. When ferromagnetic order breaks the degeneracy of the electronic bands and splits them into the spin-up majority and spin-down minority electronic bands, quasiparticle excitations between the spin-up and spin-down flat bands should form a narrow localized spin-excitation Stoner continuum coexisting with well-defined spin waves in the long wavelengths. Here we report inelastic neutron scattering studies of spin excitations in 2D metallic Kagome lattice antiferromagnetic FeSn and paramagnetic CoSn, where angle resolved photoemission spectroscopy experiments found spin-polarized and nonpolarized flat bands, respectively, below the Fermi level. Although our initial measurements on FeSn indeed reveal well-defined spin waves extending well above 140 meV coexisting with a flat excitation at 170 meV, subsequent experiments on CoSn indicate that the flat mode actually arises mostly from hydrocarbon scattering of the CYTOP-M commonly used to glue the samples to aluminum holder. Therefore, our results established the evolution of spin excitations in FeSn and CoSn, and identified an anomalous flat mode that has been overlooked by the neutron scattering community for the past 20 years.

Inelastic neutron scattering and low-energy excitation of amorphous SF6 hydrate prepared by vapor-deposition technique

2003 ◽  
Vol 81 (1-2) ◽  
pp. 107-114 ◽  
Author(s):  
O Yamamuro ◽  
T Matsuo ◽  
I Tsukushi ◽  
N Onoda-Yamamuro
Keyword(s):  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Annealed Sample ◽  
Low Energy ◽  
Energy Excitation ◽  
Hydrogen Bond Formation ◽  
Crystalline Sample ◽  
Two Samples ◽  
Vapor Deposition Technique

Amorphous SF6 hydrate (SF6·17H2O) was prepared by depositing the mixed vapor onto a substrate kept at about 8 K. The inelastic neutron-scattering spectra of the as-deposited sample and those annealed at about 120 and 150 K were measured at 50 K in the energy range below 100 meV. The first two samples were considered to be in amorphous states while the third one was in a crystalline state. The librational frequency of the water molecule (at around 60 meV) is smaller in the order of (as-deposited sample) < (annealed sample) < (crystalline sample). This indicates that the strength of the intermolecular hydrogen bonds is (crystalline sample) > (annealed sample) > (as-deposited sample). The spectra below 10 meV were compared with our previous data of pure vapor-deposited amorphous ices and those doped with methanol (CD3OH). The low-energy excitation (E < 6 meV) differed drastically depending on the dopants, i.e., the scattering intensity was enhanced by methanol doping but reduced by SF6 doping. This may be because the hydrogen-bond formation was hindered by methanol doping but promoted rather more by SF6 doping because of the hydrophobic interaction as in clathrate hydrates. PACS Nos.: 61.12Ex, 63.50tx

Spin Dynamics in the Metallic State of YBa2(Cu0.98 Zn0.02) 3O6+x

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3330-3334 ◽  
Author(s):  
Y. Sidis ◽  
P. Bourges ◽  
B. Hennion ◽  
R. Villeneuve ◽  
G. Collin ◽  
...  
Keyword(s):  
Inelastic Neutron Scattering ◽  
Spin Dynamics ◽  
Inelastic Neutron ◽  
Resonance Peak ◽  
Low Energy ◽  
Metallic State ◽  
Magnetic Fluctuations ◽  
Local Enhancement ◽  
Compound I ◽  
Nonmagnetic Impurities

Inelastic neutron scattering measurements have been carried out on a YBa2(Cu0.98-Zn0.02)3O 6+x single crystal in both underdoped (x = 0.7) and overdoped (x = 0.97) regimes. In the zinc substituted system, spin dynamics is drastically changed in respect to the pure compound: (i) the "resonance peak" almost vanishes, (ii) the spin gap is filled, (iii) new antiferromagnetic excitations are found at low energy. These new magnetic fluctuations, which persist in the normal state, account for a local enhancement of AF correlations around nonmagnetic impurities. Besides, it is worth emphasizing that features, not directly related to superconductivity, i.e., the contribution to the spin dynamics apart from the resonance peak and the "spin pseudo-gap" observed in the underdoped regime above T c , coexist with the new low energy magnetic fluctuations.

scholarly journals Decay and renormalization of a longitudinal mode in a quasi-two-dimensional antiferromagnet

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Seung-Hwan Do ◽  
Hao Zhang ◽  
Travis J. Williams ◽  
Tao Hong ◽  
V. Ovidiu Garlea ◽  
...  
Keyword(s):  
Inelastic Neutron Scattering ◽  
Longitudinal Mode ◽  
Wave Theory ◽  
Inelastic Neutron ◽  
Low Energy ◽  
Many Body ◽  
Longitudinal Modes ◽  
Quantum Magnet ◽  
Energy Mode ◽  
The Many

AbstractAn ongoing challenge in the study of quantum materials, is to reveal and explain collective quantum effects in spin systems where interactions between different modes types are important. Here we approach this problem through a combined experimental and theoretical study of interacting transverse and longitudinal modes in an easy-plane quantum magnet near a continuous quantum phase transition. Our inelastic neutron scattering measurements of Ba2FeSi2O7 reveal the emergence, decay, and renormalization of a longitudinal mode throughout the Brillouin zone. The decay of the longitudinal mode is particularly pronounced at the zone center. To account for the many-body effects of the interacting low-energy modes in anisotropic magnets, we generalize the standard spin-wave theory. The measured mode decay and renormalization is reproduced by including all one-loop corrections. The theoretical framework developed here is broadly applicable to quantum magnets with more than one type of low energy mode.

Inelastic neutron scattering study of low-energy excitations in vapor-deposited glassy propylene

1997 ◽  
Vol 106 (8) ◽  
pp. 2997-3002 ◽  
Author(s):  
Osamu Yamamuro ◽  
Itaru Tsukushi ◽  
Takasuke Matsuo ◽  
Kiyoshi Takeda ◽  
Toshiji Kanaya ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Low Energy ◽  
Scattering Study ◽  
Neutron Scattering Study
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