• Professor
    • Alexey Kimel
    • Radboud University - The Netherlands
    • Spectroscopy

Femtosecond opto-magnetism: terra incognita, discoveries and lucky coincidences

Due to the property of electron to have spin and due to quantum mechanical spin-spin exchange interaction, spins in such materials as Fe, Co and Ni can be ordered resulting in the strongest quantum mechanical phenomenon at our planet – magnetism. The problem of magnetism can be greatly simplified by accepting so-called macrospin approximation, introducing macroscopic order parameter and employing the methods of thermodynamics. In my talk I will show that exciting magnets with femtosecond flashes of light on a time scale of the exchange interaction brings generates a strongly non-equilibrium state in which the macrospin approximation fails, conventional models of magnetism based thermodynamics are no longer valid, physics of magnetism becomes counter-intuitive and the progress in the field is the result of lucky coincidences.

About

A. V. Kimel is professor and chair of the department Ultrafast Spectroscopy of Correlated Materials at Radboud University in Nijmegen. He is an expert in the area of ultrafast spectroscopy of condensed matter with an emphasis on magnetism and ultrafast magnetization dynamics. He is actively involved in the development of novel approaches for ultrafast and energy efficient magnetic recording with light, manipulation, control and detection of spin waves and spin currents in the THz spectral range (THz magnonics and THz spintronics). He received a number of prestigious fellowships and awards including VENI (2004), VIDI (2006), VICI (2017) and Radboud Science Award (2017).