This work centers around employing magnetic tight binding to study
defects in body centred cubic iron, a material of potentially great
importance as a structural component in hydrogen fusion power plants.
An existing d-band tight binding model was extended to include charge.
The first task was to develop a working scheme for calculating spins and
charges self consistently. This was achieved using an extended form of
the Harris-Foulkes functional and implemented with a generalisation of
the Newton-Raphson minimisation procedure. Having established such
a scheme it was tested on bulk structures, point defects and straight
dislocations. The motion of dislocations and the opposition to this was
also considered though calculation of Peierls barriers.