Magnetic imaging under high pressure with a spin-based quantum sensor integrated in a van der Waals heterostructure

Pressure is a powerful tool for tuning the magnetic properties of van der Waals magnets owing to their weak interlayer bonding. However, local magnetometry measurements under high pressure still remain elusive for this important class of emerging materials. Here we demonstrate magnetic imaging of a van der Waals magnet under high pressure with sub-micron spatial resolution, using a two-dimensional (2D) quantum sensing platform based on boron-vacancy ( $V_B^{-}$ ) centers in hexagonal boron nitride (hBN). We first analyze the performances of $V_B^{-}$ centers in hBN for magnetic imaging under pressures up to few GPa, and we then use this 2D sensing platform to investigate the pressure-dependent magnetization in micrometer-sized flakes of 1T-CrTe₂. Besides providing a new path for studying pressure-induced phase transitions in van der Waals magnets, this work also opens up interesting perspectives for exploring the physics of 2D superconductors under pressure via local measurements of the Meissner effect.