Thin film magnetometer - with thin ferromagnetic film and coil etc. providing alternating auxiliary field with a component in the plane of film

摘要

Magnetometer comprises a thin film of ferromagnetic material (I) with an axis of anisotropy of known orientation lying in the plane of the film; means for stimulating a magnetic auxiliary field with a component in the plane of the film; and means for detecting changes in the magnetisation of the film; in which (i) the (I) is of the type which exhibits an anisotropic magnetoresistive effect, such as the planar Hall effect or the planar magnetoresistive effect; (ii) a source is provided to pass an electric current through the film; (iii) the detecting means are arranged to detect the voltage over the two connections on the thin ferromagnetic film (formed by the planar magnet-resistive effect) or across the two Hall-voltage contacts (using the planar Hall effect), the voltage being representative of one component of a magnetic field to be measured in a direction perpendicular to that of the magnetic auxiliary field; and (iv) the magnetic auxiliary field is of such a strength that the ferromagnetic material is satd.