Seminars Archive

Observing phonon-magnon dynamics in low dimensional quantum magnets with time-domain heat conduction measurements.

Abstract
Phonon-magnon interactions play a crucial role in a variety of phenomena in magnetic materials such as energy transport, spin coherence and the onset of spin-Peierls instabilities in low dimensional materials. However, measuring such dynamics in antiferromagnets has proven difficult, and its role in determining the quasi-static heat transport properties has been the subject of much debate over the last thirty years. To try to solve this conundrum we have performed dynamic heat transport measurements using optical time-domain techniques. By modeling the experiment as a two-carrier diffusion process we measured exceptionally long phonon-magnon interaction times in a recently discovered class of low-dimensional quantum antiferromagnets. These results provide a simple, direct way to measure the elusive phonon-magnon dynamics in antiferromagnetic materials in view of their employment as the building blocks of the emerging field of spin caloritronics, to achieve the manipulation of heat-carrying spin currents to build logic gates and devices.