Theory of magnetic cold-work peak in ferromagnetic materials

The magnetic after effect due to dislocations is investigated for three types of configurations: i) randomly distributed immobile point defects, ii) Cottrell clouds, iii) strongly bound defects in the dislocation core. It is shown that only the case of the mobile Cottrell cloud leads to a simple Debye process, whereas the other cases must be described by a more general relaxation function. The role of point defects in the core of dislocations is studied in some details. In this case the relaxation time is found to be determined mainly by the binding energy of the impurity atoms to the dislocation core.