Nonlinear NMR dynamics in hyperpolarized liquid 3He

Emmanuel Baudin (1) , Michael E. Hayden (2) , Geneviève Tastevin (1) , Pierre-Jean Nacher (1)

1 LKB (Lhomond) - Laboratoire Kastler Brossel
2 SFU - Physics Department

In a highly polarized liquid (laser-polarized 3He-4He mixtures in our experiment), dipolar magnetic interactions within the liquid introduce a significant nonlinear and nonlocal contribution to the Bloch equation that leads to instabilities during NMR evolution. We have launched a study of these instabilities using spin echo techniques. At high magnetizations, a simple 180° rf pulse fails to refocus magnetization, so we use a standard solid-state NMR pulse sequence: the magic sandwich. We report an experimental and numerical investigation of the effect of this sequence on unstable NMR evolution. Using a series of repeated magic sandwich sequences, the transverse magnetization lifetime can be increased by up to three orders of magnitude.

Mots clés: precession instabilities; nonlinear NMR; dipolar interaction; hyperpolarized Helium; magic sandwich

Domaines: Autre [cond-mat.other]; Physique Générale [physics.gen-ph]

Emmanuel Baudin, Michael E. Hayden, Geneviève Tastevin, Pierre-Jean Nacher. Nonlinear NMR dynamics in hyperpolarized liquid 3He. 2007. ⟨hal-00180383v1⟩