Non-equilibrium dynamics of spin-lattice coupling
Hiroki Ueda, Roman Mankowsky, E. Paris, Mathias Sander, Yunpei Deng, B. Liu, Ludmila Leroy, Abhishek Nag, Elizabeth Skoropata, Chennan Wang, Victor Ukleev, Gérard Sylvester Perren, Janine Dössegger, Sabina Gurung, Cristian Svetina, Elsa Abreu, Matteo Savoini, T. Kimura, L. Patthey, E. Razzoli, H. Lemke, Steven L. Johnson, U. Staub
Abstract
Abstract Quantifying the dynamics of normal modes and how they interact with other excitations is of central importance in condensed matter. Spin-lattice coupling is relevant to several sub-fields of condensed matter physics; examples include spintronics, high- T c superconductivity, and topological materials. However, experimental approaches that can directly measure it are rare and incomplete. Here we use time-resolved X-ray diffraction to directly access the ultrafast motion of atoms and spins following the coherent excitation of an electromagnon in a multiferroic hexaferrite. One striking outcome is the different phase shifts relative to the driving field of the two different components. This phase shift provides insight into the excitation process of such a coupled mode. This direct observation of combined lattice and magnetization dynamics paves the way to access the mode-selective spin-lattice coupling strength, which remains a missing fundamental parameter for ultrafast control of magnetism and is relevant to a wide variety of materials.