Atom jumps in intermetallics: From bulk to thin films

In long-range ordered intermetallics, special sublattices of the crystal structure in the disordered state can be distinguished leading to certain differences between atomic diffusion and pure ordering processes. It is therefore of great importance to study the atom jump processes in intermetallics which determine the limits of alloy stability. This is in turn a necessary precondition for materials design and alloy development. Recently, ferromagnetic intermetallics showing L10-type atomic ordering moved into the focus of interest. These alloys display a marked mechanical and magnetic anisotropy with the c-axis of the tetragonally distorted ordered domains as the 'easy axis' of magnetization. High density magnetic recording may be achieved in these materials when stabilised as low-dimensional magnetic structures. We have studied changes of long-range order during different heat treatments in the bulk and are currently extending our methods to L1 0-ordered thin films. Recent results of diffraction, resistivity measurement, magnetization hysteresis loops, Mößbauer spectroscopy and Monte-Carlo simulation in both geometries are compared.