Spin Dependent Impurity Effects on the 2D Frustrated Magnetism of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>NiGa</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>

Nambu, Yusuke; Nakatsuji, Satoru; Maeno, Y.; Okudzeto, Edem K.; Chan, Julia Y.

doi:10.1103/physrevlett.101.207204

Cited by 24 publications

(34 citation statements)

References 22 publications

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“…Figure 2 shows the best fit to the data. We find T 0 = 225 (20) We have also recorded spectra after field cooling the sample in a B ext = 10 mT longitudinal field; see Fig. 1.…”

Section: Fig 2 (Color Online)mentioning

confidence: 71%

“…≃ θ CW /10) for NiGa 2 S 4 and FeGa 2 S 4 , respectively. The magnetic contributions to the specific heat C M (T ) of the two compounds are field insensitive with a T 2 dependence at low temperature, and they match one another after appropriate rescaling 20 . While C M /T is negligible for T → 0 K in NiGa 2 S 4 , an appreciable value is measured for FeGa 2 S 4 .…”

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confidence: 88%

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Evidence for an exotic magnetic transition in the triangular spin system FeGa2S4

et al. 2012

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We report positive muon spin relaxation measurements on the triangular lattice magnetic system FeGa2S4. A magnetic transition not previously detected by specific heat and magnetic susceptibility measurements is found in zero field at T * ≃ 30 K. It is observed through the temperature dependencies of the signal amplitude and the spin-lattice relaxation rate. This transition is therefore not a conventional magnetic phase transition. Since persistent spin dynamics is observed down to 0.1 K, the ground state cannot be of the canonical spin-glass type, which could be suggested from hysteresis effects in the bulk susceptibility below T f ≃ 16 K. These results are compared to those found for the isomorph NiGa2S4. It is argued that the fate of the transition, which has been interpreted in terms of the Z2 topological transition in this latter system, is probably different in FeGa2S4.

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“…Figure 2 shows the best fit to the data. We find T 0 = 225 (20) We have also recorded spectra after field cooling the sample in a B ext = 10 mT longitudinal field; see Fig. 1.…”

Section: Fig 2 (Color Online)mentioning

confidence: 71%

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confidence: 88%

Evidence for an exotic magnetic transition in the triangular spin system FeGa2S4

et al. 2012

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“…The semi-classical description of spin degrees of freedom thus cannot account for the impurity-spin size dependence of doped NiGa 2 S 4 [18,27,28]. Specifically, the lowtemperature T 2 asymptotic behaviour of C M is preserved only for integer impurity spins that support a quadrupole moment [14,15].…”

Section: Fig 2: (Color Online)mentioning

confidence: 99%

Spin Fluctuations from Hertz to Terahertz on a Triangular Lattice

et al. 2015

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The temporal magnetic correlations of the triangular lattice antiferromagnet NiGa2S4 are examined through thirteen decades (10 −13 −1 sec) using ultra-high-resolution inelastic neutron scattering, muon spin relaxation, AC and nonlinear susceptibility measurements. Unlike the short-ranged spatial correlations, the temperature dependence of the temporal correlations show distinct anomalies. The spin fluctuation rate decreases precipitously upon cooling towards T * = 8.5 K, but fluctuations on the microsecond time scale then persist in an anomalous dynamical regime for 4 K < T ≤ T * . As this time scale exceeds that of single site dynamics by six orders of magnitude, these fluctuations bear evidence of emergent degrees of freedom within the short-range correlated incommensurate state of NiGa2S4.PACS numbers: 75.40. Gb, 78.70.Nx, 76.75.+i, 75.30.Cr The two dimensional triangular lattice plays a prominent role in the field of frustrated magnetism. While it now seems clear that the conventional triangular lattice antiferromagnet has long-range non-collinear 120 degree Néel order irrespective of the spin quantum number, S [1-3], experiments on materials with generalized longer range interactions, spin-orbit interactions, as well as lattice distortions point to a rich variety of phases in the vicinity of the Néel phase [4,5]. In the quantum limit (S = 1/2) first considered by Anderson [6], experiments on organic materials suggest a gapless spin liquid with a spinon Fermi surface may exist near the metal insulator transition [7]. Recent exact-diagonalization showed such quantum spin-liquid states can be stabilized by the presence of randomness in the near-neighbor interactions [8]. Deep in the insulating limit, neutron scattering experiments suggest conventional spin waves may be supplemented or replaced by a spinon-like continuum even when long-range order is present [9].For larger spin quantum numbers theoretical [10] and experimental [11] work points to complex slow spin dynamics that is still poorly understood. Here we focus on * Present address: Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577, Japan such dynamics in the S = 1 triangular lattice antiferromagnet NiGa 2 S 4 [12, 13], which is distinguished by a 2D incommensurate critical wave vector and the potential for spin-nematic interactions [14,15]. Using high energy resolution inelastic neutron scattering, neutron spin echo, muon spin relaxation (µSR), and AC magnetometry, we provide evidence for emergent MHz spin dynamics over a wide range of temperatures. We argue such slow spin dynamics is associated with emergent topologically protected degrees of freedom inherent to incommensurate magnetism on the triangular lattice.Polycrystalline samples of NiGa 2 S 4 were synthesized by solid state reaction described elsewhere [16]. Elasticchannel data were taken on the GPTAS and HER tripleaxis spectrometers at the JRR-3 research reactor. The backscattering data were taken on the high flux backscattering (HFBS) instrument at the NIST Cente...

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“…14) In this paper, we report the experimental and analytical results of electron spin resonance (ESR) and magnetization measurements on single crystals of NiGa 2 S 4 , which were performed to clarify the spin dynamics in more detail than those in our previous short report. 15) We found unique dynamics of a Z 2 -vortex-induced effect on the temperature dependence of ESR absorption linewidth.…”

Section: Introductionmentioning

confidence: 99%

“…These interesting experimental results have stimulated further theoretical and experimental studies of this compound. [5][6][7][8][9][10][11][12][13][14][15][16] A theoretical analysis taking bilinearbiquadratic exchange interactions into consideration seemed to account for some of such unique experimental results. [6][7][8] Strong third-neighbor and negligible second-neighbor exchange interactions are suggested by results of photoem- ission spectroscopy 9) and ab initio calculations using the density functional theory (DFT).…”

Section: Introductionmentioning

confidence: 99%

High-Field ESR and Magnetization of the Triangular Lattice Antiferromagnet NiGa₂S₄

et al. 2010

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We report the experimental and analytical results of electron spin resonance (ESR) and magnetization at high magnetic fields of up to about 68 T of the quasi two-dimensional triangular lattice antiferromagnet NiGa 2 S 4 . From the temperature evolution of the ESR absorption linewidth, we find a distinct disturbance of the development of the spin correlation by Z 2 -vortices between 23 and 8.5 K. Below T v ¼ 8:5 K, spin-wave calculations based on a 57 spiral spin order well explain the frequency dependence of the ESR resonance fields and high-field magnetization processes for H k c and H ? c, although the magnetization for H ? c at high fields is different from the calculated one. Furthermore, we explain the field-independent specific heat with a T 2 dependence by the same spin-wave calculation, but the magnitude of specific heat is much less than the observed one. The single ion anisotropy constant (2010) 023701] is a necessary condition for the realization of a Z 2 -vortex-induced topological transition, which would be destroyed by an extremely small D 6 ¼ 0 in a classical nearest-neighbor spin model owing to the large . Accordingly, these results suggest the occurrence of a Z 2 -vortex-induced topological transition at T v and indicate quantum effects beyond the descriptions based on the above classical spin models, for example, those due to quadrupolar correlations.

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Spin Dependent Impurity Effects on the 2D Frustrated Magnetism ofNiGa2S4

Cited by 24 publications

References 22 publications

Evidence for an exotic magnetic transition in the triangular spin system FeGa2S4

Evidence for an exotic magnetic transition in the triangular spin system FeGa2S4

Spin Fluctuations from Hertz to Terahertz on a Triangular Lattice

High-Field ESR and Magnetization of the Triangular Lattice Antiferromagnet NiGa₂S₄

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Spin Dependent Impurity Effects on the 2D Frustrated Magnetism ofNiGa2S4

Cited by 24 publications

References 22 publications

Evidence for an exotic magnetic transition in the triangular spin system FeGa2S4

Evidence for an exotic magnetic transition in the triangular spin system FeGa2S4

Spin Fluctuations from Hertz to Terahertz on a Triangular Lattice

High-Field ESR and Magnetization of the Triangular Lattice Antiferromagnet NiGa2S4

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Product

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High-Field ESR and Magnetization of the Triangular Lattice Antiferromagnet NiGa₂S₄