¹H NMR and magnetization measurements of a nanostructured composite material of the Mg₂Ni-H system synthesized by reactive mechanical grinding

¹H NMR spectra and magnetization have been measured for a nanostructured Mg₂Ni-H system. ¹H MAS NMR spectra indicate the presence of four phases; α-Mg₂NiH_x, β-Mg₂NiH₄, α-MgH_x and β-MgH₂. Most of the hydrogens are contained in the disordered β-Mg₂NiH₄ phase. Magnetization consists of superparamagnetic and paramagnetic ones. The former has its origin in Ni particles formed during the hydrogenation. The latter is greater than the values of crystalline α-Mg₂NiH_x and β-Mg₂NiH₄. ¹H NMR line width increases with the decrease in temperature linearly, most of which is of dipolar origin. The hydrogen is more mobile in the disordered β-Mg₂NiH₄ phase than in the crystalline counterpart.