Spin-wave spectrum and inelastic neutron scattering by magnons inNd2CuO4

1994 ◽  
Vol 49 (2) ◽  
pp. 1170-1181 ◽  
Author(s):  
V. L. Sobolev ◽  
H. L. Huang ◽  
Yu. G. Pashkevich ◽  
M. M. Larionov ◽  
I. M. Vitebsky ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Spin Wave ◽  
Inelastic Neutron Scattering ◽  
Wave Spectrum ◽  
Inelastic Neutron ◽  
Spin Wave Spectrum

scholarly journals Inelastic Neutron Scattering Investigations of an Anisotropic Hybridization Gap in the Kondo Insulators: CeT2Al10 (T=Fe, Ru and Os)

2016 ◽  
Vol 257 ◽  
pp. 11-25 ◽  
Author(s):  
Devashibhai T. Adroja ◽  
Y. Muro ◽  
Toshiro Takabatake ◽  
M.D. Le ◽  
H.C. Walker ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Spin Wave ◽  
Inelastic Neutron Scattering ◽  
Wave Spectrum ◽  
Magnetic Ordering ◽  
Inelastic Neutron ◽  
Spin Gap ◽  
Kondo Insulators ◽  
Anisotropic Exchange ◽  
Magnetic Ordering Temperature

The recent discovery of topological Kondo insulating behaviour in strongly correlated electron systems has generated considerable interest in Kondo insulators both experimentally and theoretically. The Kondo semiconductors CeT2Al10 (T=Fe, Ru and Os) possessing a c-f hybridization gap have received considerable attention recently because of the unexpected high magnetic ordering temperature of CeRu2Al10 (TN=27 K) and CeOs2Al10 (TN=28.5 K) and the Kondo insulating behaviour observed in the valence fluctuating compound CeFe2Al10 with a paramagnetic ground state down to 50 mK. We are investigating this family of compounds, both in polycrystalline and single crystal form, using inelastic neutron scattering to understand the role of anisotropic c-f hybridization on the spin gap formation as well as on their magnetic properties. We have observed a clear sign of a spin gap in all three compounds from our polycrystalline study as well as the existence of a spin gap above the magnetic ordering temperature in T=Ru and Os. Our inelastic neutron scattering studies on single crystals of CeRu2Al10 and CeOs2Al10 revealed dispersive gapped spin wave excitations below TN. Analysis of the spin wave spectrum reveals the presence of strong anisotropic exchange, along the c-axis (or z-axis) stronger than in the ab-plane. These anisotropic exchange interactions force the magnetic moment to align along the c-axis, competing with the single ion crystal field anisotropy, which prefers moments along the a-axis. In the paramagnetic state (below 50 K) of the Kondo insulator CeFe2Al10, we have also observed dispersive gapped magnetic excitations which transform into quasi-elastic scattering on heating to 100 K. We will discuss the origin of the anisotropic hybridization gap in CeFe2Al10 based on theoretical models of heavy-fermion semiconductors.

scholarly journals The investigation of Neutron Scattering In Spin Waves Theory of Ferromagnetic Crystals

2014 ◽  
Vol 8 (4) ◽  
Author(s):  
Azadeh Farzaneh ◽  
Mohammad Reza Abdi ◽  
Khadije Rezaee Ebrahim Saraee
Keyword(s):  
Neutron Scattering ◽  
Spin Wave ◽  
Cross Section ◽  
Inelastic Neutron Scattering ◽  
Spin Waves ◽  
Wave Theory ◽  
Spin Correlation ◽  
Inelastic Neutron ◽  
Magnetic Behaviour ◽  
Spin Interaction

Inelastic neutron scattering, probing the temporal spin-spin correlation at the different microscopic scale, is a powerful technique to study the magnetic behaviour of ferromagnetic crystals. In addition, high penetration power of neutron in samples has made it as a useful way for spin-spin interaction in neutron scattering. Changes in the magnetic cross section in term of different energy transfer and temperatures are calculated for nickel and iron as transition metals in Heisenberg model versus spin wave theory by considering atomic form factor. Finally, the effect of magnetic structure and behaviour of crystal in measuring cross-section shows that increasing temperature results in the Cross-section increase Also, the existence of propagating spin waves below Tc is compared in Ni and Fe in different momentum transfers. The relation of spin wave energy with temperature dependence of nickel has created different behaviour in the changes of cross section rather than iron.

Multimodeling Approach to Ferromagnetic Spin-Wave Excitations in the High-Spin Cluster Mn18Sr Observed by Inelastic Neutron Scattering

2019 ◽  
Vol 58 (16) ◽  
pp. 11256-11268
Author(s):  
Siyavash Nekuruh ◽  
Joscha Nehrkorn ◽  
Krunoslav Prsa ◽  
Jan Dreiser ◽  
Ayuk M. Ako ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Spin Wave ◽  
High Spin ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Spin Cluster ◽  
Spin Wave Excitations

scholarly journals Signatures of a liquid-crystal transition in spin-wave excitations of skyrmions

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Narayan Mohanta ◽  
Andrew D. Christianson ◽  
Satoshi Okamoto ◽  
Elbio Dagotto
Keyword(s):  
Spin Wave ◽  
Magnetic Order ◽  
Inelastic Neutron Scattering ◽  
Spin Dynamics ◽  
Wave Spectrum ◽  
Exchange Interactions ◽  
Inelastic Neutron ◽  
Spin Wave Excitations ◽  
Crystal Transition ◽  
Dynamics Simulations

AbstractUnderstanding the spin-wave excitations of chiral magnetic order, such as the skyrmion crystal (SkX), is of fundamental interest to confirm such exotic magnetic order. The SkX is realized by competing Dzyaloshinskii-Moriya and ferromagnetic-exchange interactions with a magnetic field or anisotropy. Here, we compute the dynamical spin structure factor, using Monte Carlo and spin dynamics simulations, extracting the spin-wave spectrum in the SkX, in the vicinity of the paramagnet to SkX transition. Inside the SkX, we find six spin-wave modes, which are supplemented by another mode originating from the ferromagnetic background. Above the critical temperature Ts for the skyrmion crystallization, we find a diffusive regime, reminiscent of the liquid-to-crystal transition, revealing that topological spin texture of skyrmionic character starts to develop above Ts as the precursor of the SkX. We discuss the opportunities for the detection of the spin waves of the SkX using inelastic-neutron-scattering experiments in manganite-iridate heterostructures.

scholarly journals Suppressed-moment 2-k order in the canonical frustrated antiferromagnet Gd2Ti2O7

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Joseph A. M. Paddison ◽  
Georg Ehlers ◽  
Andrew B. Cairns ◽  
Jason S. Gardner ◽  
Oleg A. Petrenko ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Spin Wave ◽  
Inelastic Neutron Scattering ◽  
Magnetic Moments ◽  
Magnetic Ordering ◽  
Thermal Fluctuation ◽  
Inelastic Neutron ◽  
Scattering Measurements ◽  
Theoretical Predictions ◽  
Powder Samples

AbstractIn partially ordered magnets, order and disorder coexist in the same magnetic phase, distinct from both spin liquids and spin solids. Here, we determine the nature of partial magnetic ordering in the canonical frustrated antiferromagnet Gd2Ti2O7, in which Gd3+ spins occupy a pyrochlore lattice. Using single-crystal neutron-diffraction measurements in applied magnetic field, magnetic symmetry analysis, inelastic neutron-scattering measurements, and spin-wave modeling, we show that its low-temperature magnetic structure involves two propagation vectors (2-k structure) with suppressed ordered magnetic moments and enhanced spin-wave fluctuations. Our experimental results are consistent with theoretical predictions of thermal fluctuation-driven order in Gd2Ti2O7, and reveal that inelastic neutron-scattering measurements on powder samples can solve the longstanding problem of distinguishing single-k and multi-k magnetic structures.

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