Magneto-optic properties of macroscopic ferrimagnets

A new class of two phased materials, called macroscopic ferrimagnets, displays many properties associated with ferrimagnetism including magnetic compensation points. A typical material system which shows this phenomenon is cobalt containing ≅100 Å precipitates of EuS. The negative exchange in these systems is relatively weak so the remanent magneto-optic properties show the ferrimagnetic state, but at fields above 2 to 3 T, alignment of both the Co and EuS with the field can occur. In addition to the usual magnetic compensation point at which the sign of the magneto-optic loop reverses, we observe a second, magneto-optic, compensation point which occurs when the Kerr rotation of the two phases are equal and opposite