Field Emission Magnetometers

The feasibility and development of a field emission based anisotropic vector magnetometer is presented. Within this scope current magnetic sensing technology is investigated and compared. The advantages of, and need for, a field emission based magnetic sensor are then discussed. The magnetic sensing device presented uses a sharp field emitting tip with a radius of the order of 100nm which is fabricated using standard silicon processing techniques. Under a vacuum and at room temperature, an electric field is applied to a surrounding gate electrode which extracts a beam of electrons from a cathode tip, this electron beam is incident upon two separate anode electrodes: In the absence of an external magnetic field the electron current incident on each of these two electrodes is equal, while in the presence of a magnetic field the Lorenz force skews the beam towards one of the electrodes, resulting in a differential current which is proportional to the magnetic field.

Autorentext

Dr J. French has worked within such diverse fields as broadcasting and aerospace, applying his electronic and software engineering skills. This Ph.D. thesis, on the physics of field emission magnetic sensors, was awarded in 2009 from University College London.