The global need for data storage only grows year on year, imposing additional
hardware requirements for devices we use in our day-to-day lives. However, we
are fast approaching the technical limit for data bit density in devices currently in
circulation. We therefore have to look to different materials and device types to
circumvent these technical limitations. Antiferromagnetic materials have received
interest in this field due to their impervious nature with respect to stray magnetic
fields, allowing closer data bit packing, and the terahertz (THz) frequency spin
dynamics present in these materials is an order of magnitude higher than that
present in ferromagnets, allowing faster data read/write. For these materials to
be used effectively for this purpose, however, the magnetic structure of these ma-
terials needs to be thoroughly understood. This, presently, is not the case. A
significant area of interest is the observed presence of magnetic domains in these
materials, which can not be explained by magnetostatics, the case for ferromag-
nets. Works have been undertaken to explain the presence of these domains, using
the magnetoelastic coupling. These important works gave analytic explanations
as to how antiferromagnetic domains form for specific sample geometries and
boundary conditions. We seek to expand on these important works by creating
a software package to examine the magnetoelastic effect on antiferromagnets for
general sample geometries and device level (> 10nm) lengthscales. We use the
phase field model as the basis of our work, allowing us to explore larger length-
scales without massively increased computational costs due to us not having to
consider precessional dynamics, and adapt a modular approach to the problem.
This thesis details how we developed our software package, and how we tested it.
We demonstrate the large effect that inclusion defects have on the magnetic struc-
ture of antiferromagnets, showing the antiferromagnetic domains produced as a
result. We analyse how the size, shape and location of these defects, aswell as al-
tering the magnetoelastic coupling strength, affect the nucleation of these domains
and the resultant change in shape and size of the domains produced. The effect
of these defects on already present domain textures (domain walls) is also studied,
showing even the presence of a single small defect is enough to distort the domain
wall. In producing this software package, we believe we have given a platform for
further examination of the magnetic structure of antiferromagnets, and in doing so
inform future implementation of antiferromagnets in data storage devices.
