Märta Tschudin: Quantum Sensing of 2D Magnets

The recent discovery of two-dimensional (2D) magnetic materials [1] has sparked wide interest in the scientific community due to their potential for a novel atomic-scale platform hosting exotic spin-textures and exhibiting different magnetic phases [2]. Future advances of these materials and their applications, however, rely on quantitative understanding of their magnetic properties at the nanoscale. Magnetic imaging using a single spin in diamond has proven to be an excellent tool for probing magnetism in van der Waals (vdW) materials with nanoscale resolution [3]. In our group we employ a scanning technique with single Nitrogen-Vacancy (NV) centers embedded in an all-diamond scanning probe to image nanoscale magnetization patterns in a range of 2D materials. In this talk I will discuss our quantitative studies of magnetism in the vdW magnet chromium triiodide (CrI₃) [3], where we investigated the interlayer exchange coupling in this material and shed light on the correlation between structural order and magnetization of the material. I will then describe our most recent efforts of imaging layered, antiferromagnetic 2D magnets, where we study spin textures down to the monolayer limit. With our experiments we gain insight into different magnetic phases, domain formation and magnetic anisotropies in these systems. I will conclude by giving an outlook on how NV centers could be used to study dynamical phenomena such as spin-waves in vdW magnets in the future.

[1] Huang et al., Nature 546, 270; C. Gong et al, Nature 546, 265 (2017)

[2] Gibertini et al., Nature Nano. 14, 408 (2019)

[3] Thiel et al., Science 364, 973 (2019)