Neutron Scattering Studies of Non-Linear Systems

Abstract

This article describes a number of neutron scattering experiments which have been performed recently on systems which exhibit non-linear behaviour. Examples chosen include the incommensurably modulated insulator thiourea for which defect-induced effects mimic intrinsic non-linear behaviour, an aggregated gold colloid which displays fractal properties and two low-dimensional magnets. Experiments on the latter systems have been carried out with neutron polarisation analysis, a powerful technique which allows different components of the magnetic fluctuation spectrum to be measured independently. All experiments have been chosen to illustrate “a lesson from the past” or “a prospect for the future.”