Magnetization and Spin Dynamics in Two-Dimensional Magnets

The discovery of magnetism in two-dimensional (2D) van der Waals (vdW) materials has flourished a new endeavor of fundamental problems in magnetism. In this talk, we will discuss the magnetization and spin dynamics in two types of 2D magnets: a room-temperature vdW magnetic crystal Fe5GeTe2 with a Curie temperature Tc = 332 K and Cu(1,3-bdc), a quasi-2D magnet with a Kagome lattice. Ferromagnetic resonance was performed with external magnetic fields applied along the c-axis (H║c) and the ab-plane (H║ab). We have found a sizable Landé g-factor difference between the H║c and H║ab cases for both Fe5GeTe2 and Cu(1,3-bdc). The FMR measurements have also revealed that Fe
5
GeTe
2
has a damping constant comparable to Permalloy. Our experiments highlight key information regarding the magnetic state and spin scattering processes in 2D magnets, which can lead to implementations of 2D magnets based spintronic devices.