  Mixtures of Fe and Cu powders are cold-compacted and subsequently deformed
with severe plastic deformation by high-pressure torsion, leading to bulk
samples. The dilution of Fe in the Cu matrix is investigated with
SQUID-magnetometry, whereas the magnetic properties change as a function of
Fe-content from a frustrated regime to a thermal activated behaviour. The
magnetic properties are correlated with the microstructure, investigated by
synchrotron X-ray diffraction and atom probe tomography. Annealing of the
as-deformed states leads to demixing and grain growth, with the coercivity as a
function of annealing temperature obeying the random anisotropy model. The
presented results show that high-pressure torsion is a technique capable to
affect the microstructure even on atomic length scales.
