Anomalous spin echoes in highly polarised liquid helium mixtures

Tastevin, Geneviève; Piegay, N.; Marion, François; Nacher, Pierre-Jean

doi:10.1016/s0921-4526(02)01945-2

“…The decay of the average transverse magnetisation is thus expected to remain dominated by dipolar-induced instabilities at high magnetisation densities. Indeed, early attempts to generate single Hahn spin echoes and Carr-Purcell spin echo trains in highly polarised 3 He-4 He dilute mixtures have led to the observation of multiple echoes [8] and of non-exponential decay [5], respectively. (traces a and c), spin echoes have the shapes that are expected given the sample geometry and the gradient strengths.…”

Section: Echo Trains and Diffusion-induced Attenuationmentioning

confidence: 99%

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

Baudin

¹

,

Hayden

²

,

Tastevin

³

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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“…The decay of the average transverse magnetisation is thus expected to remain dominated by dipolar-induced instabilities at high magnetisation densities. Indeed, early attempts to generate single Hahn spin echoes and Carr-Purcell spin echo trains in highly polarised 3 He- 4 He dilute mixtures have led to the observation of multiple echoes [8] and of non-exponential decay [5], respectively.…”

Section: Echo Trains and Diffusion-induced Attenuationmentioning

confidence: 99%

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

Baudin,

Hayden,

Tastevin

et al. 2007

Preprint

Self Cite

0

View full text Add to dashboard Cite

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.

show abstract