In magnetic and magneto-optical switching devices, in particular, used for recording purposes, information bits are stored as oppositely oriented magnetic domains representing the values “0” and “1” respectively. The conventional way of switching spins or magnetic domains is to apply an external magnetic field along the direction of spins, opposite to their initial orientation. This is a rather slow reversal process. Alternatively the external field can be applied perpendicular and not parallel to the spin orientation. This will trigger a much faster reversal process via a precessional motion of the spins around the external applied field. A plurality of magnetic and magneto-optical recording devices is being currently manufactured using such principles for reversing magnetization and thereby write and re-write the information.
A new type of such magnetic recording devices designed to achieve ultra-high data storage densities, is the so called heat assisted magnetic recording (HAMR). Here a high anisotropy magnetic medium is heated by a laser beam such that the external applied field can still be efficient in reversing the magnetization. However, this approach does not simplify the magnetic recording process but instead involves more elements leading to high manufacturing costs of the magnetic devices as well as higher power consumption. Furthermore, by I. Tudosa et all., Nature 428, 831 (2004) and C. H. Back et al., Nature 428, 808 (2004) it has been demonstrated that the ultimate speed of magnetic switching triggered by a magnetic field is bounded in the picosecond time scale. Since the demand for ever increasing the density of data storage requires increasing of the magnetization switching speed too, new and faster ways of switching the magnetization other than by magnetic fields are desirable. Incorporated by reference, in Kimel et al. “Ultrafast non-thermal control of magnetization by instantaneous photomagnetic pulses”, Nature Letters, Published online 25 May 2006, further referred to as “Nature Letters article” non-thermal excitation was demonstrated for dielectric materials. Also incorporated by reference, in Hansteen et al. “Femtosecond photomagnetic switching of spins in Ferrimagnetic Garnet Films”, Physical Review Letters, 047402 (2005), further referred to as the PRL article, small angle magnetization precessions were demonstrated to have been successfully controlled. The materials in which optically induced effects were demonstrated are insulating materials.