The importance and nature of magnetic and lattice degrees of freedom and their interaction in transition metal magnets has been investigated. Two different alloy systems in which the magnetic 3D electrons either had localised or itinerant characteristics were chosen. As an example of localised behaviour, Heusler alloys in which the magnetic moment was confined to Mn atoms were chosen, e.g. Pd2MnIn. The manganese atoms are separated by more than 4.6Å. These materials provide a good approximation to a Heisenberg system, having long-range interactions. [Continues.]
A doctoral thesis submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.