Nuclear magnetic resonance measurements of the proton spin-lattice relaxation rate in C15-type Mo2HfH0.4 were performed at 20 to 420K using resonance frequencies of 13 to 90MHz. The temperature dependence of the relaxation rate was found to exhibit 2 peaks. This was consistent with the coexistence of 2 types of H-hopping, having different frequency scales. The experimental results were analysed so as to yield the parameters of H motion, and the electronic (Korringa) contribution to the relaxation rate. The results supported the idea that the ratio of the characteristic frequencies of the 2 types of H motion in AB2 C15 compounds was related to the ratio of the metallic radii of A and B.

Hydrogen Diffusion in C15-Type HfMo2H0.4 - Nuclear Magnetic Resonance Evidence of Two Frequency Scales of H Hopping. A.V.Skripov, A.V.Soloninin, A.P.Stepanov, V.N.Kozhanov: Journal of Physics - Condensed Matter, 1999, 11[50], 10393-400