ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The defect pyrochlores H2Ta2O6, HTaWO6, and their hydrates have been studied by proton nuclear magnetic resonance. Rigid lattice spectra of H2Ta2O6 and HTaWO6 exhibit a large Lorentzian contribution which indicates a statistical distribution of the protons over the 48 f sites of the structure and implies the pairing of protons bonded to the same oxygen [r(H–H)=1.5 A(ring)]. Long range diffusive motion is deduced from the relaxation rates; in all four compounds the diffusion mechanism can be explained by using two independent correlation times τ1 and τ2. The activation energy corresponding to the jump of a proton to the nearest neighbor vacant position is the same (E1=0.15 eV) for three of the pyrochlores. The low temperature spin lattice relaxation of the anhydrous compounds H2Ta2O6 and HTaWO6 is governed by the existence of unequal potential wells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.449960
