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Nacher, Pierre-Jean; Tastevin, Geneviève; Villard, Bérengère; Piegay, N.; Marion, François; Sauer, Karen L.

doi:10.1023/a:1017512921929

Cited by 16 publications

(8 citation statements)

References 6 publications

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“…Investigations for different sample shapes are in progress in laserpolarized liquids. 16 Dipolar field effects similar to those presented in this paper are expected to be observed in conventional high-resolution NMR experiments in liquids, as soon as relaxation and radiation-damping processes get under efficient control in high-field spectrometers. 11,17 We thank Jean Jeener for stimulating discussions and for communicating unpublished results.…”

supporting

confidence: 64%

“…Yet they form a consistent extension to the He data, which correspond to higher F dip ͑100-600 Hz͒ in a similar geometry. 8,16 Our Xe experiment shows that the decay rates in this small angle regime strongly depend on the sample-field orientation. This unanticipated result needs further investigation and explanation.…”

mentioning

confidence: 80%

“…This confirms recent results obtained in laser-polarized He. 10,16 Below the onset of instabilities, long-lived magnetization modes result in the observed spectral clustering. These spatially nonuniform modes should be damped by spin diffusion.…”

mentioning

confidence: 99%

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NMR instabilities and spectral clustering in laser-polarized liquid xenon

et al. 2001

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To study how highly magnetized liquids behave in NMR experiments, we have performed low-field NMR on laser-polarized liquid 129 Xe, with nuclear polarization of up to 6%. Contrary to conventional NMR results, we find that instabilities develop after a large pulse, leading to an unexpectedly abrupt decay of the signal. In contrast, the NMR spectrum after a small pulse collapses to a series of unusually sharp lines ͑spectral cluster-ing͒, whose widths correspond to precession lifetimes longer than a half minute. We discuss the key role of long-range dipolar coupling in such spin dynamics.

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confidence: 64%

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confidence: 80%

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NMR instabilities and spectral clustering in laser-polarized liquid xenon

et al. 2001

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“…Beyond the usual range of average dipolar fields produced by bulk water, the domain of large dipolar fields in solutions has also been investigated using numerical simulations [23,24] and highly polarized 3 He and 129 Xe [25][26][27][28]. The larger range of accessible densities and nuclear polarizations using these hyperpolarized nuclei has revealed the potential existence of collective behaviors observed as spectral clustering [29], chaotic time evolution leading to a rapid crunch of the magnetization [23,[30][31][32][33] which can nevertheless be delayed by repeated magic sandwich sequences [34], and the observation of multiple maser emissions [35,36]. More recently two groups [37,38] have reported the use of the generic CRAZED approach for observing i-MQC [12,39] in 13 C or 1 H samples whose magnetization was previously enhanced by Dynamic Nuclear Polarization (DNP).…”

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confidence: 99%

Multiple echoes due to distant dipolar fields in NMR of hyperpolarized noble gas solutions

et al. 2013

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We report on multiple echo measurements in hyperpolarized liquids using optically pumped spin-1/2 noble gas atoms: either 129 Xe dissolved in cyclohexane or 3 He dissolved in superfluid 4 He. An NMR pulse sequence 90 • − τ − 90 • (with slice-selective flipping pulses for 129 Xe experiments) was used and long echo trains have been observed in the presence of applied gradients due to average dipolar fields typically one order of magnitude larger than those of bulk water in high magnetic fields. We show that a mean field description is valid for explaining the multiple echoes observed in these liquids, even for spin temperatures as low as 10 mK for 129 Xe or 10 µK for 3 He, and the echoes originate from the distant dipolar fields within the samples. Numerical lattice simulations have been used to assess the effects of slice selection and of finite sample size in addition to those of atomic diffusion. They account for the observed echo widths and amplitudes much better than previously published models which disregard finite size effects that appear to be of key importance. This opens the way to using multiple echoes resulting from distant dipolar fields for the determination of the absolute magnetization in hyperpolarized liquids without signal calibration.

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“…They introduce a nonlocal contribution to the evolution of magnetisation and give rise to complex non-linear behaviour. Spectacularly abrupt decays of NMR free induction signals have been observed at large tip angles in several laser-polarised liquid systems [1], and have been explained by the development of unstable inhomogeneous magnetisation patterns that grow exponentially in time [2]. The onset of precession instabilities is a generic feature of highly magnetised systems, and is related to turbulent spin motion [2].…”

Section: Introductionmentioning

confidence: 99%

NMR Time Reversal Experiments in Highly Polarised Liquid 3He-4He Mixtures

et al. 2007

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Long-range magnetic interactions in highly magnetised liquids (laser-polarised 3 He-4 He dilute mixtures at 1 K in our experiment) introduce a significant non-linear and non-local contribution to the evolution of nuclear magnetisation that leads to instabilities during free precession. We recently demonstrated that a multi-echo NMR sequence, based on the magic sandwich pulse scheme developed for solid-state NMR, can be used to stabilise the magnetisation against the effect of distant dipolar fields. Here, we report investigations of echo attenuation in an applied field gradient that show the potential of this NMR sequence for spin diffusion measurements at high magnetisation densities.

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Cited by 16 publications

References 6 publications

NMR instabilities and spectral clustering in laser-polarized liquid xenon

NMR instabilities and spectral clustering in laser-polarized liquid xenon

Multiple echoes due to distant dipolar fields in NMR of hyperpolarized noble gas solutions

NMR Time Reversal Experiments in Highly Polarised Liquid 3He-4He Mixtures

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