Abstract
In a mixed magnetic system, such as a ferromagnetic alloy, there is a spatial inhomogeneity in the distribution of magnetization and this gives rise to a diffuse scattering of neutrons which is strictly elastic. The observation of this diffuse scattering is capable of giving information about the magnetization distribution on an atomic scale. In practice it is necessary to assume suitable models for the way in which each atom affects the magnetization in its immediate environment. Various models are described and it is shown that, even for concentrated alloys where a number of effects must be allowed for, the cross-section formulae are simple. It follows that neutron experiments on mixed magnetic systems can be interpreted in terms of functions of physical significance.