Neutron Scattering Studies of Diffusion in Solids

Abstract

Neutron scattering is an extremely versatile tool in condensed matter research. In particular it is well suited for the study of fast atomic transport phenomena and has thus found important applications in those fields of physics, chemistry, metallurgy and biology, where such phenomena occur. This chapter will show how the scattering of slow neutrons can be used to learn about the microscopic mechanisms of atomic diffusion in solids. This will be done in three steps. The first step will be an introduction to the theory of neutron scattering; this will be presented in sections (1) and (2). Secondly, we will discuss the way in which physical models of systems to be studied enter into theoretical expressions for the scattered neutron intensity. This will enable us to compare, in section (3), the results of neutron scattering experiments with the theories of atomic diffusion which we wish to apply. The remaining sections of the chapter deal with applications concerned with local diffusion in molecular crystals (section 4), interstitialcy and vacancy diffusion in metals (section 5) and fast ion diffusion in solid electrolytes (section 6).