TABLE OF CONTENTS This article is focused on the discussion of one important experimental method for measurements of magnetic excitations in solids, i.e., inelastic neutron scattering (INS): a method that has been in the past and that will be in the future the method of choice in this field.
In the first part, an overview is given on magnetic neutron cross-sections, on the range of experimentally accessible transfers of momentum and energy (( Q; ?)-range), and on important types of neutron spectrometers that are used for the measurements of magnetic excitations.
In the second part, the hierarchy of relevant solid-state interactions and the involved energy scales will be discussed for compounds containing the magnetic elements with 3 d-, 4 f-, and 5 f-electrons in open atomic shells.
In the third and last part, elementary magnetic excitations like those from spin waves, crystal-field transitions, inter-multiplet transitions, and spin fluctuations will be presented in relation to their occurrence in bulk magnetic materials containing the elements with 3 d-, 4 f-, and 5 f-electrons.
An early review on magnetic excitations was given by (Stirling and McEwen 1986).
The interaction of thermal neutrons with matter is twofold: the nuclear interaction with the atomic nuclei and the magnetic interaction of the neutron s magnetic dipole moment with the magnetic field B created by the unpaired electrons in the sample. A comprehensive theoretical treatment is given in the two volumes of the book...
