Role of compensation points in all-optical magnetization switching

We study theoretically the role of compensation points in all-optical magnetization switching (AOS) in rare-earth transition-metal ferrimagnets. We use the s-d model in which localized spins are coupled with spins of itinerant electrons via the s-d exchange interaction. The main advantage of the model is that it considers the dynamics of both localized and itinerant spin population. We show that the compensation temperature, which is relevant to AOS, is determined by the net spin polarization, i.e., by the sum of the spin polarizations of localized and itinerant spins. This temperature does not coincide exactly with either the magnetization compensation temperature or the angular momentum compensation temperature.