Spintronics has the potential to overcome fundamental limitations of conventional electronics.
In particular, the manipulation of spins in magnetic materials offers the perspective of a data recording, processing and transfer technology operating at least 1000 times faster than current schemes and, most importantly, with negligible heat dissipations. Insulating antiferromagnets have emerged as especially promising in materials in this sense, as in these systems the generation and manipulation of coherent collective spin excitations have been reported. While so far almost the entire focus of the scientific community was placed on low-energy spin waves, the time- and length- scale of the spin dynamics can be driven to the extreme limits in a given magnetic materials if high-energy magnons, i.e. magnons with wavevector near the edges of the Brillouin zone, are excited.
In my project, I am following an approach to coherent manipulation of solids in the femtosecond timescale based on the use of femtosecond laser pulses in the mid-infrared range. In this spectral range, it is possible to resonantly drive high-energy magnon modes on the femtosecond timescale, which represents an unprecedented perturbation of the magnetic ground state, enabled only very recently by the development of a custom laser system. Preliminary results show that intense excitation of high-energy magnons induces spin dynamics in a highly perturbed regime, in which the magnon dispersion is significantly altered. In addition, during my PhD project further development of the experimental set-up will be realised. For instance, the possibility to perform optical and magneto-optical measurements in cryogenic conditions will be established, as much as the ability to perform a temporally- and spectrally-resolved pump-probe-experiment completely in the mid-infrared portion of the spectrum.