[Seminar] - Paradoxes of ultrafast antiferromagnetism and writing of antiferromagnetic bits

Abstract: Ultrafast spin dynamics in antiferromagnets is paradoxical. While commonly accepted Curie-Neumann’s principle states that “the symmetries of the causes are to be found in the effects” and implies that a magnetic field cannot control antiferromagnetic Néel vector, rapidly changing THz magnetic field appears to “violate” this principle and can effectively excite spins in antiferromagnets . In this ultrafast regime, laser-induced spin dynamics in antiferromagnets is intrinsically non-linear, where new channels of spin-lattice interaction open-up, the principle of superposition fails, i.e. 1+1>2, and antiferromagnets appear to host even more channels to excite spins than one can find in ferromagnets. We will review recent progress in ultrafast antiferromagnetic spin dynamics, highlight the recently discovered mechanism enabling control of antiferromagnetic spins by a THz electric field, and discuss the conditions required for reliable writing of stable antiferromagnetic bits.

Séminaire organisé dans le cadre du programme interdisciplinaire MAT-PULSE (Materials and Physics @ Ultimate
Scale: Nanotech for a sustainable digital world)