Persistence of singlet fluctuations in the coupled spin tetrahedra system Cu<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>Te<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>O<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>5</mml:mn></mml:msub></mml:math>Br<mml:math xmlns:mml="h

Baek, S.‐H.; Choi, K.-Y.; Berger, H.; Büchner, B.; Grafe, H.-J.

doi:10.1103/physrevb.86.180405

Cited by 12 publications

(4 citation statements)

References 28 publications

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“…Two I = 3 2 -isotopes with 100% natural abundance in total and relatively large quadrupole moments on both nuclei identifies Br-NMR and NQR as a powerful technique which is frequently applied on quantum spin systems and other forms of matter. [22][23][24][25] Our Br magnetic resonance study presented here aims for the consistent determination of the quadrupole coupling constant ν Q and the asymmetry parameter η from NMR and NQR. Figure 2 shows the field sweep 1 H-and 19 F-NMR spectra measured at a fixed frequency of 84.44 MHz for different temperatures.…”

Section: Introductionmentioning

confidence: 99%

Magnetic resonance as a local probe for kagomé magnetism in Barlowite Cu4(OH)6FBr

Ranjith

Klein

Tsirlin

et al. 2018

Sci Rep

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Temperature- and field-dependent 1H-, 19F-, and 79,81Br-NMR measurements together with zero - field 79,81Br-NQR measurements on polycrystalline samples of barlowite, Cu4(OH)6FBr are conducted to study the magnetism and possible structural distortions on a microscopic level. The temperature dependence of the 79,81Br-NMR spin-lattice relaxation rates 1/T1 indicate a phase transition at TN 15 K which is of magnetic origin, but with an unusually weak slowing down of fluctuations below TN. Moreover, 1/T1T scales linear with the bulk susceptibility which indicates persisting spin fluctuations down to 2 K. Quadupolare resonance (NQR) studies reveal a pair of zero-field NQR- lines associated with the two isotopes of Br with the nuclear spins of I = 3/2. Quadrupole coupling constants of vQ ≃ 28.5 MHz and 24.7 MHz for 79Br- and 81Br-nuclei are determined from Br-NMR and the asymmetry parameter of the electric field gradient was estimated to η ≃ 0.2. The Br-NQR lines are consistent with our findings from Br-NMR and they are relatively broad, even above TN. This broadening and the relative large η value suggests a symmetry reduction at the Br- site reflecting the presence of a local distortion in the lattice. Our density-functional calculations show that the displacements of Cu2 atoms located between the kagome planes do not account for this relatively large η. On the other hand, full structural relaxation, including the deformation of kagome planes, leads to a better agreement with the experiment.

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Section: Introductionmentioning

confidence: 99%

Magnetic resonance as a local probe for kagomé magnetism in Barlowite Cu4(OH)6FBr

Ranjith

Klein

Tsirlin

et al. 2018

Sci Rep

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“…The origin of the spin gap may be related to the fact that the coordination number of each spin in Cu 3 TeO 6 is only 4. This may cause each Cu hexagon to behave as a spin cluster weakly coupled to others, and the clusterlike interaction may cause the strong upshift of the spectral weight [27] giving rise to the unusual spin gap behavior in the short-ranged ordered state. In this case, the suppression of the spin susceptibility below T * could be understood in terms of short-ranged AFM spin correlations related to the competition between intra-and inter-hexagon couplings.…”

Section: Discussionmentioning

confidence: 99%

Unusual spin pseudogap behavior in the spin web lattice Cu$_3$TeO$_6$ probed by $^{125}$Te nuclear magnetic resonance

Baek,

Yeo,

Park

et al. 2021

Preprint

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We present a 125 Te nuclear magnetic resonance (NMR) study in the three-dimensional spin web lattice Cu3TeO6 which harbors topological magnons. The 125 Te NMR spectra and the Knight shift K as a function of temperature show a drastic change at TS ∼ 40 K much lower than the Néel ordering temperature TN ∼ 61 K, providing evidence for the first-order structural phase transition within the magnetically ordered state. Most remarkably, the temperature dependence of the spin-lattice relaxation rate T −1 1 unravels spin-gap-like magnetic excitations, which sharply sets in at T * ∼ 75 K, the temperature well above TN. The spin gap behavior may be understood by weakly dispersive optical magnon branches of high-energy spin excitations originating from the unique corner-sharing Cu hexagon spin-1/2 network with low coordination number.

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“…Generally, the spin gap Δ/kB obtained from 1/T1 is larger than the true spin gap Δmin (q) occurring at a specific point q. [29][30][31] This is because1/T1 maps out the qaverage of the dynamical spin susceptibility, 1/T1 ~ T ΣqA 2 (q)χ''(q,ω0). Here, A(q) is the form factor of hyperfine interactions, and ω0 is the nuclear Larmor frequency.…”

Section: Exhibited Inmentioning

confidence: 98%

Emergent spin-liquid-like state in the bond-disordered breathing pyrochlore

Lee

et al. 2020

Preprint

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A breathing pyrochlore system is predicted to host a variety of quantum spin liquids. However, perturbations beyond nearest-neighbor Heisenberg interaction are an obstacle to identifying such exotic states. Here, we utilize a bond-alternating disorder to tune a magnetic ground state in the Cr-based breathing pyrochlore. By combining thermodynamic and magnetic resonance techniques, we provide experimental signatures of a spin-liquid-like state in LiGa1-xInxCr4O8 (x=0.2), namely, a nearly T2-dependent magnetic specific heat and a persistent spin dynamics by muon spin relaxation (μSR). Moreover, 7Li NMR, ZF-μSR, and ESR unveil the dichotomic nature of both temporal and thermal spin fluctuations: slowly fluctuating tetramer singlets at high temperatures and a fast fluctuating spin-liquid-like state at low temperatures. Our results suggest that a bond disorder in the breathing pyrochlore offers a new route to achieve an unexplored state of matter.

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Persistence of singlet fluctuations in the coupled spin tetrahedra system Cu2Te2O5Br
S.‐H. Baek
¹
,
K.-Y. Choi
²
,
H. Berger
³

et al.

Cited by 12 publications

References 28 publications

Magnetic resonance as a local probe for kagomé magnetism in Barlowite Cu4(OH)6FBr

Magnetic resonance as a local probe for kagomé magnetism in Barlowite Cu4(OH)6FBr

Unusual spin pseudogap behavior in the spin web lattice Cu$_3$TeO$_6$ probed by $^{125}$Te nuclear magnetic resonance

Emergent spin-liquid-like state in the bond-disordered breathing pyrochlore

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Persistence of singlet fluctuations in the coupled spin tetrahedra system Cu2Te2O5BrS.‐H. Baek1, K.-Y. Choi2, H. Berger3 et al.

Cited by 12 publications

References 28 publications

Magnetic resonance as a local probe for kagomé magnetism in Barlowite Cu4(OH)6FBr

Magnetic resonance as a local probe for kagomé magnetism in Barlowite Cu4(OH)6FBr

Unusual spin pseudogap behavior in the spin web lattice Cu$_3$TeO$_6$ probed by $^{125}$Te nuclear magnetic resonance

Emergent spin-liquid-like state in the bond-disordered breathing pyrochlore

Contact Info

Product

Resources

About

Persistence of singlet fluctuations in the coupled spin tetrahedra system Cu2Te2O5Br
S.‐H. Baek
¹
,
K.-Y. Choi
²
,
H. Berger
³

et al.