Crystal‐field ‘‘dressing’’ and enhanced magnetoelastic effects

Hybridization of moderately delocalized f electrons with band electrons gives rise to a highly anisotropic two‐ion interaction. If a bare, point‐charge‐like crystal field is included, it is ‘‘dressed’’ by the hybridization both through the two‐ion interaction and through the modification of the single‐ion interactions. We have investigated the relative effects of the anisotropic two‐ion interaction on cubic and tetragonal crystal‐field terms in the distorted paramagnetic phase. We have found a difference in the degree and the temperature dependence of the dressing of the two terms. This provides a possible explanation for enhanced magnetoelastic effects in materials such as CeAl2.