SIKA—the multiplexing cold-neutron triple-axis spectrometer at ANSTO

Wu, Chun Min; Deng, Guochu; Gardner, J. S.; Vorderwisch, P.; Li, W.-H.; Yano, Shinichiro; Peng, Jen-Chih; Imamovic, Eno

doi:10.1088/1748-0221/11/10/p10009

Cited by 40 publications

(22 citation statements)

References 11 publications

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“…The extremely large anisotropy of magnetization between B ∥ c and B ∥ ab geometry confirms the c-axis polarized magnetism [35][36][37]. Neutron scattering experiments were performed using a thermal triple-axis spectrometer (Taipan) and a cold triple-axis spectrometer (Sika) at Australian Centre for Neutron Scattering, ANSTO, Australia [41,42]. For Taipan experiments, the final neutron energy was fixed to E f = 14.87 meV, using a pyrolytic graphite filter, double focusing monochromator, and vertical focusing analyzer.…”

Section: Experimental Methodsmentioning

confidence: 81%

Spin excitations and spin wave gap in the ferromagnetic Weyl semimetal Co3Sn2S2

Liu

Gao

et al. 2020

Sci. China Phys. Mech. Astron.

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We report a comprehensive neutron scattering study on the spin excitations in the magnetic Weyl semimetal Co3Sn2S2 with a quasi-two-dimensional structure. Both in-plane and out-of-plane dispersions of the spin waves were revealed in the ferromagnetic state. Similarly, dispersive but damped spin excitations were found in the paramagnetic state. The effective exchange interactions were estimated using a semi-classical Heisenberg model to consistently reproduce the experimental TC and spin stiffness. However, a full spin wave gap below Eg = 2.3 meV was observed at T = 4 K. This value was considerably larger than the estimated magnetic anisotropy energy (~0.6 meV), and its temperature dependence indicated a significant contribution from the Weyl fermions. These results suggest that Co3Sn2S2 is a three-dimensional correlated system with a large spin stiffness, and the low-energy spin dynamics can interplay with the topological electron states.

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Section: Experimental Methodsmentioning

confidence: 81%

Spin excitations and spin wave gap in the ferromagnetic Weyl semimetal Co3Sn2S2

Liu

Gao

et al. 2020

Sci. China Phys. Mech. Astron.

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“…Inelastic neutron scattering experiments were performed on both the thermal-neutron and cold triple-axis spectrometers, TAIPAN [19] and SIKA [20] at OPAL, respectively. On A single-crystal sample of CNO with a mass of about 2 g was mounted on an Al sample holder and aligned in the ac plane for the experiments.…”

Section: Methodsmentioning

confidence: 99%

Spin dynamics and magnetoelectric coupling mechanism of Co4Nb2O9

et al. 2018

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Neutron powder diffraction experiments reveal that Co 4 Nb 2 O 9 forms a noncollinear in-plane magnetic structure with Co 2+ moments lying in the ab plane. The spin-wave excitations of this magnet were measured by using inelastic neutron scattering and soundly simulated by a dynamic model involving nearest-and next-nearestneighbor exchange interactions, in-plane anisotropy, and the Dzyaloshinskii-Moriya interaction. The in-plane magnetic structure of Co 4 Nb 2 O 9 is attributed to the large in-plane anisotropy, while the noncollinearity of the spin configuration is attributed to the Dzyaloshinskii-Moriya interaction. The high magnetoelectric coupling effect of Co 4 Nb 2 O 9 in fields can be explained by its special in-plane magnetic structure.

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“…The experimental data were processed into the scattering function S(q, ω) by using the software package HORACE from ISIS [30]. The cold-neutron triple-axis spectrometer SIKA [31] at OPAL was used to measure the spin-wave dispersion along the Q H , Q K , and Q L directions within the ac and bc scattering planes.…”

Section: Methodsmentioning

confidence: 99%

Spin dynamics of edge-sharing spin chains in SrCa13Cu24O41

Deng

Mole

et al. 2018

Phys. Rev. B

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The low-energy magnetic excitation from the highly Ca-doped quasi-one-dimensional magnet SrCa 13 Cu 24 O 41 was studied in the magnetic ordered state by using inelastic neutron scattering. We observed the gapless spin-wave excitation, dispersive along the a and c axes but nondispersive along the b axis. Such excitations are attributed to the spin wave from the spin-chain sublattice. Model fitting to the experimental data gives the nearest-neighbour interaction J c as 5.4 meV and the interchain interaction J a = 4.4 meV. J c is antiferromagnetic and its value is close to the nearestneighbour interactions of the similar edge-sharing spin-chain systems such as CuGeO 3 . Comparing with the hole-doped spin chains in Sr 14 Cu 24 O 41 , which shows a spin gap due to spin dimers formed around Zhang-Rice singlets, the chains in SrCa 13 Cu 24 O 41 show a gapless excitation in this study. We ascribe such a change from gapped to gapless excitations to holes transferring away from the chain sublattice into the ladder sublattice upon Ca doping. IntroductionThe dimensionality of a spin system is one of the most important characters for its underlying physics. Most of the three-dimensional (3D) Heisenberg magnetic systems can be well described by the linear spin-wave theory (LSWT), which was developed decades ago 1 . Upon reducing a magnetic system from 3D to two or one dimensions (2D or 1D), quantum fluctuations will be substantially enhanced, which consequently results in various intriguing and exotic physical phenomena. 2 The theoretical work by Bethe more than 80 years ago predicted that the S = ½ antiferromagnetic Heisenberg chain cannot form a long-range magnetic ordering due to strong quantum fluctuations. 3 A domain-wall-like spin excitation called "spinon" was proposed later, which has been experimentally confirmed in various real magnetic systems. Unfortunately, except for the S = ½ spinchain case, no exact analytical solution like Bethe's work has been developed for other 1D antiferromagnetic Heisenberg spin systems. However, numerical methods were widely employed to study the ground states of more complicated 1D systems, 4 such as 1D spin chains with S > ½ and spin ladders with even/odd legs 5 , and successfully predicted their ground state and dynamic behaviours.As the simplest case of a 1D spin system, Cu 2+ (S = ½) spin chains are extensively investigated due to their close relationship with the cuprate high-temperature superconductors. 5 CuO 2 chains can be divided into two classes, corner-sharing spin chains and the edge-sharing spin chains. The former are building blocks of cuprate superconductors and spin ladders. In corner-sharing CuO 2 chains, the exchange interaction between the nearest neighbours (NN) comes from the super-exchange through the ~180 o Cu-O-Cu pathway. 6 Such an interaction is experimentally demonstrated to be quite strong, ranging from 100 meV to 160 meV. 7 In contrast, the NN exchange interaction along edge-sharing spin chains is much weaker due to the ~90 o Cu-O-Cu pathway. [8][9][10] The...

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SIKA—the multiplexing cold-neutron triple-axis spectrometer at ANSTO

Cited by 40 publications

References 11 publications

Spin excitations and spin wave gap in the ferromagnetic Weyl semimetal Co3Sn2S2

Spin excitations and spin wave gap in the ferromagnetic Weyl semimetal Co3Sn2S2

Spin dynamics and magnetoelectric coupling mechanism of Co4Nb2O9

Spin dynamics of edge-sharing spin chains in SrCa13Cu24O41

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