Hybrid Quantum Sensing Using Boron Vacancy Centers and 2D CrSBr

The negatively charged boron vacancy (V_B⁻) in hexagonal boron nitride (hBN) has emerged as a robust, optically addressable spin sensor in a van der Waals platform. Compared to the nitrogen-vacancy center in diamond, V_B⁻ ensembles offer a single out-of-plane symmetry axis and atomically small sensor–sample standoff, enabling vector-selective, near-field magnetic sensing. However, V_B⁻ cannot sense in-plane fields and has a sensing range limited to ~1 T due to increased RF loss at high frequency. Here, we demonstrate the first optically detected antiferromagnetic resonance (ODAFMR) of the layered antiferromagnet CrSBr using V_B⁻ centers hosted in isotopically purified h¹⁰B¹⁵N. The hBN/CrSBr heterostructure exhibits clear field- and temperature-tunable magnon resonances at tens of GHz. These results establish a hybrid, chip-proximal sensing platform that enables vector field sensing and operation over a large magnetic field range. The same architecture can further enable spatially resolved mapping of magnon modes and domain structures.