Quasi-elastic Neutron Scattering to probe ionic conduction

2024

This study of QENS analysis has been undertaken on a N a − β′′ − alumina. Two incident

energies, 1.95 meV and 3.55 meV have been used in a range of -1.5,+1.5 and -2,+2 and

data were collected at 140K and 400K. Two components have been found by fitting the

data with Lorentzian model. It has been observed that a broader component corresponds

to fast diffusion because of the presence of large number of vacancies in the structure,

while, a narrow component shows a slower and more localized jumps. The wider compo-

nent displayed a Q-dependence which suggest that the Q.E signal is mainly because of

long range diffusion of N a+, while the narrow width component showed Q-independence.

A Chudley-Elliot model has been utilized using residence time of 1 ps and jump length

of 3 Å. The agreement has been observed between the broader width parameters over Q

and the model, which verified that N a+ exhibits jump diffusion.

UIS