Curie-point switching in Mn-Bi films

The magnetization within micrometer-size spots on Mn-Bi films was Curie-point switched with a laser in static applied magnetic fields. Such switching was found to be a continuous rather than a binary process, in that the average magnetization within a spot could be switched to any value between
+I_{s}
and
-I_{s}
by varying the applied field. The dependence of the magnetization after switching on field was measured quantitatively via the magnetooptic effect. Switched spots were examined under oil-immersion optics to reveal the magnetization distribution responsible for this dependence.