Magnetostrictive displacements around a domain wall junction: elastic field calculation and application to X-ray topography

The elastic field around wall junctions in magnetostrictive ferromagnetic materials is characteristic of the displacements around a disclination. Wall junctions are therefore very often paired in two quasi-disclinations of opposite signs. The classical case of the junction of two 90° walls and one 180° wall is studied in detail. This configuration frequently occurs in {100} Fe 3% Si specimens and has already been extensively observed by means of Lang X-ray topography. The junction is assumed to be perpendicular to the surface of the sample and we have computed the elastic field, taking into account the surface terms. The wide dynamical image observed on X-ray topographs when μt is equal to 2 or 3 seems to be due mostly to surface terms.