Diffusion slowdown in the nanostructured liquid Ga-Sn alloy

Abstract

The diffusion of gallium in liquid Ga-Sn alloy embedded into different porous silica matrices was studied by NMR. Spin relaxation was measured for two gallium isotopes, Ga-71 and Ga-69, at two magnetic fields. Pronounced rise of quadrupole contribution to relaxation was observed for the nanostructured alloy which increased with decreasing the pore size. The correlation time of atomic mobility was evaluated and found to be much larger than in the relevant bulk melt which evidenced a pronounced diffusion slowdown in the Ga-Sn alloy under nanoconfinement. It is shown that the diffusion was slower by a factor of 30 for the alloy within 7 nm pores. The spectral densities of electric field gradients at zero frequency were found to double for the finest pores. The Knight shift was found to decrease but slightly for the nanostructured alloy.