On the resolution of slow-neutron spectrometers. IV. The triple-axis spectrometer resolution function, spatial effects included

Popovici, M.

doi:10.1107/s0567739475001088

Cited by 97 publications

(44 citation statements)

References 1 publication

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“…This produces a whole range of often misinterpreted effects in measurements with a cTAS which has been subject to thorough study in the past [39][40][41][42]. The vertically scattering analyzer setup also produces resolution effects of which two are directly evident in our data.…”

Section: Magnetic Excitations In Mnfmentioning

confidence: 90%

Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

Toft-Petersen

Groitl

Kure

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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a b s t r a c tA thorough experimental characterization of a multiplexing backend with multiple energy analysis on a cold-neutron triple axis spectrometer (cTAS) is presented. The prototype employs two angular segments ( θ 2 -segments) each containing five vertically scattering analyzers (energy channels), which simultaneously probe an energy transfer range of 2 meV at the corresponding two scattering angles. The feasibility and strength of such a vertically scattering multiple energy analysis setup is clearly demonstrated. It is shown, that the energy resolution near the elastic line is comparable to the energy resolution of a standard cTAS. The dispersion relation of the antiferromagnetic excitations in MnF 2 has been mapped out by performing constant energy transfer maps. These results show that the tested setup is virtually spurion free. In addition, focusing effects due to (mis)matching of the instrumental resolution ellipsoid to the excitation branch are clearly evident.

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Section: Magnetic Excitations In Mnfmentioning

confidence: 90%

Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

Toft-Petersen

Groitl

Kure

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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“…The instrumental resolution was calculated in the Popovici approximation. 32 FIG. 6: (Color online) Diffuse NSF and SF scattering in the (0kl) reciprocal plane at various temperature where the polarization Z is parallel to the a-axis.…”

Section: B Zero Field Short Range Ordermentioning

confidence: 99%

Absence of long-range order in the frustrated magnet SrDy2O4 due to trapped defects from a dimensionality crossover

et al. 2017

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Magnetic frustration and low dimensionality can prevent long range magnetic order and lead to exotic correlated ground states. SrDy 2 O 4 consists of magnetic Dy 3+ ions forming magnetically frustrated zig-zag chains along the c-axis and shows no long range order to temperatures as low as T = 60 mK. We carried out neutron scattering and AC magnetic susceptibility measurements using powder and single crystals of SrDy 2 O 4 . Diffuse neutron scattering indicates strong one-dimensional (1D) magnetic correlations along the chain direction that can be qualitatively accounted for by the axial next-nearest neighbour Ising (ANNNI) model with nearestneighbor and next-nearest-neighbor exchange J 1 = 0.3 meV and J 2 = 0.2 meV, respectively. Three-dimensional (3D) correlations become important below T * ≈ 0.7 K. At T = 60 mK, the short range correlations are characterized by a putative propagation vector k 1/2 = (0,2 ). We argue that the absence of long range order arises from the presence of slowly decaying 1D domain walls that are trapped due to 3D correlations. This stabilizes a low-temperature phase without long range magnetic order, but with well-ordered chain segments separated by slowly-moving domain walls.

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“…First, the gaussian 4-dimensional (q, ω) modelization of the resolution ellipsoid was performed using the Popovici method [36] implemented in Rescal [37]. The model ellipsoid was then convoluted with a locally anisotropic quadratic expansion of the dispersion surface using a Monte Carlo algorithm around a reference point (ξ 0 , ω 0 ).…”

Section: D-monte Carlo Adjustmentmentioning

confidence: 99%

Low energy phonon spectrum and its parameterization in pure KTaO3 below 80 K

et al. 2000

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Abstract. High resolution data on low energy phonon branches (acoustic and soft optic) along the three principal symmetry axes in pure KTaO3 were obtained by cold neutron inelastic scattering between 10 and 80 K. Additional off-principal axis measurements were performed to characterize the dispersion anisotropy (away from the <100> and <110> axes). The parameters of the phenomenological model proposed by Vaks [28] are refined in order to successfully describe the experimental low temperature (10 < T < 100 K) dispersion curves, over an appreciable reciprocal space volume around the zone center (|q| < 0.25 rlu).The refined model, which involves only 4 temperature-independent adjustable parameters, is intended to serve as a basis for quantitative computations of multiphonon processes.

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On the resolution of slow-neutron spectrometers. IV. The triple-axis spectrometer resolution function, spatial effects included

Cited by 97 publications

References 1 publication

Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

Absence of long-range order in the frustrated magnet SrDy2O4 due to trapped defects from a dimensionality crossover

Low energy phonon spectrum and its parameterization in pure KTaO3 below 80 K

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