I have learned that there are different methods to study Hydrogen diffusion in metals, like pulsed field gradient (PFG) NMR, and quasi-elastic neutron scattering.
QENS has the advantage of giving the spatial and temporal information.
Are the both methods very effective for all the materials (here restricted in metals and alloys)?
What's the difference between them?
Are there any limits for these two methods? for examples, the covered length scale? or time scale?