Silicon vacancy center based magnetometry in isotopically purified 4H-SiC

Point defects in solid state materials are promising systems in the fields of quantum information, communications and sensing. Particular to sensing, defects with coherent spin transitions are exceptionally suited for high sensitivity, room temperature magnetic sensing at ambient conditions. Applications involving magnetic sensing with point defects have mostly been dominated by the nitrogen vacancy center in diamond, which possesses an excellent combination of spin coherence at room temperature as well as spin initialization and readout. However, spin defects in other materials have been explored as alternatives, especially in industrially mature materials such as silicon carbide. In this work we report on the improved sensitivity of a magnetic sensor system utilizing an ensemble of silicon vacancies in silicon carbide due to isotopic purification of the host crystal. A maximum sensitivity of 4 nT/√Hz is reported, limited by laser amplitude noise and external magnetic field noise. Additional sensing modalities such as angle resolved imaging and highly tunable broadband sensing are also reported.