MAGNETIC REORIENTATION TRANSITION IN EPITAXIAL GD-FILMS

The susceptibility of epitaxial Gd/W(110)-films was investigated as a function of temperature and film thickness, using a magnetooptical measurement technique. In addition to the sharp peak at the Curie temperature T(C), a second peak below T(C) was observed for film thicknesses d greater-than-or-equal-to 35 nm. This peak shifts to lower temperatures with increasing film thickness. The origin of this second susceptibility maximum has been identified as a reorientation transition of the magnetization. Results from micromagnetic calculations using bulk gadolinium parameters are fully consistent with the observed behavior.