Abstract: A magnetic field sensor employing a graphene sense layer, wherein the Lorentz force acting on charge carriers traveling through the sense layer causes a change in path of charge carriers traveling through the graphene layer. This change in path can be detected indicating the presence of a magnetic field. The sensor includes one or more gate electrodes that are separated from the graphene layer by a non-magnetic, electrically insulating material. The application of a gate voltage to the gate electrode alters the electrical resistance of the graphene layer and can be used to control the sensitivity and speed of the sensor.