Conduction-electron mediated ¹H nuclear spin-lattice relaxation in Ti₄₅Zr₃₈Ni₁₇H_x icosahedral quasicrystals

Nuclear magnetic resonance spin-lattice relaxation rates for ¹H in quasicrystalline Ti₄₅Zr₃₈Ni₁₇H_x are presented as a function of temperature and hydrogen concentration x. The temperature dependence demonstrates that the relaxation is via interaction with conduction electrons. The relaxation rate is extremely sensitive to hydrogen content, with the rate changing by a factor of as much as two for samples that differ in x by at most 2%. We interpret the changes in the conduction-electron-mediated spin-lattice relaxation as due to fine structure ('spikiness') in the electronic density ρ(E) of states and estimate that ρ(E) changes by 40% over an energy range of 75 meV.