Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS


FEMTOMAGNETISM Sintesi della relazione

Project ID: 257280
Finanziato nell'ambito di: FP7-IDEAS-ERC
Paese: Netherlands

Final Report Summary - FEMTOMAGNETISM (Femtosecond Laser Control of Spins in Magnetic Materials: from fundamentals to nanoscale dynamics)

The project has the following objectives:
• To obtain novel fundamental knowledge on ultrafast light-spin interactions
• To investigate spin dynamics after the action of the opto-magnetic pulse as well as to reveal novel scenarios for magnetization reversal triggered by short laser pulses
• realize magnetic switching with both ultrafast sub-100 ps temporal and 100 nm spatial resolution using methods of near-field optics
• initiate a breakthrough in magnetic recording and information processing technology

The project has fully achieved the goals and due to this project our understanding of ultrafast optical control of magnetism has been improved a lot. Metallic ferrimagnets such as GdFeCo and TbFeCo are just one type of model systems which have been studied in the proposal. For these ferromagnetic alloys we have demonstrated experimentally, computationally and phenomenologically that an ultrafast laser-induced heating alone can result in magnetization reversal and toggle switching (Nature-Communications doi: 10.1038/ncomms1666 (2012) and Phys. Rev. Lett 108 057202 (2012)). It has been demonstrated that using methods of near-field optics such a switching can be realized with a subwavelength spatial resolution below the diffraction limit (Nano Lett. 15 6862-6868 (2015), Nature Comm. 6 5839 (2015)). Such a subwavelength opto-magnetic recording appears to be not only ultrafast, but also energy efficient. We argue that an energy lower than 10 fJ should be sufficient to switch a 20×20 nm2 structure (Phys. Rev. B 86, 140404(R) (2012)).

In this project, a substantial progress has been also achieved in understanding of ultrafast optical control of magnetism in semiconducting and dielectric materials. New and rather unconventional experimental methods have been developed. The examples of these methods are single-shot magneto-optical imaging with femtosecond temporal and micrometer spatial resolutions (Phys. Rev. Lett. 108, 157601 (2012)), coherent control of spins at the edge of the Brillouin zone (Nature Comm. (accepted), polarization sensitive THz emission spectroscopy (Nature Comm. 6, 8190 (2015)) and pump-probe time-domain spectroscopy of ultrafast magnetization dynamics in magnetic fields up to 38 Tesla.

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