  The encapsulation of graphene in hexagonal boron nitride provides graphene on
substrate with excellent material quality. Here, we present the fabrication and
characterization of Hall sensor elements based on graphene boron nitride
heterostructures, where we gain from high mobility and low charge charier
density at room temperature. We show a detailed device characterization
including Hall effect measurements under vacuum and ambient conditions. We
achieve a current- and voltage-related sensitivity of up to 5700 V/AT and 3
V/VT, respectively, outpacing state-of- the-art silicon and III/V Hall sensor
devices. Finally, we extract a magnetic resolution limited by low frequency
electric noise of less than 50 nT/pHz making our graphene sensors highly
interesting for industrial applications.
