Optical seminar. Alexandra Kalashnikova

Alexandra Kalashnikova

Ferroics Physics Laboratory, Ioffe Institute & Department of Physics and Engineering, ITMO University

Ultrafast thermal and non-thermal phase transitions in magnetic media

Solid-solid phase transitions, when driven by an external stimulus at a subpicosecond time scale, represent a promising way to control a state of matter with unprecedented speed. In this talk we summarize results of our works on ultrafast laser-driven magnetic, structural and electronic phase transitions. First, we examine a simple idea that heating induced by a laser pulse should drive a material possessing phase transition from one phase to another, and show how a thermal spin-reorientation transition in a magnetic medium can be utilized for switching magnetization by light [1]. Then we turn to the phase transitions which rely on laser-driven electronic excitations instead of heating, and thus can be truly ultrafast. A sticking example of such transitions is an insulator-metal transition [2] found e.g. in vanadium dioxide and magnetite. In the latter material we test an idea that fast changes in electronic structure can strongly affect the magnetic properties as well and thus allow achieving non-thermal spin-reorientation transition.

[1] J. A. de Jong et al., Phys. Rev. Lett. 108, 157601 (2012).

[2] I. A. Mogunov et al., Phys. Rev. Appl. 11, 014054 (2019).