Static and dynamic magnetic properties ofHe3confined by fluorocarbon microspheres

Abstract

The magnetic properties of liquid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ confined by fluorocarbon microspheres have been studied by NMR in a large range of magnetic fields (0.03–3 T) and between 10 and 800 mK. The dynamics of the liquid magnetization are driven by the relaxation mechanisms of the adsorbed solid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ film. This relaxation is produced by the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ motion induced by quantum exchange. The spectral density of this motion has been deduced from measurements of relaxation times in the liquid. The quantum exchange in the solid layer also allows a magnetization transfer between the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and substrate ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ spins. Magnetic susceptibility measurements have also been done as function of pressure and temperature. A growth of adsorbed solid is observed as the liquid pressure increases. We also demonstrated the possibility of producing enhanced liquid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ magnetization by nuclear dynamic polarization.