(under subclass 244) Subject matter wherein the apparatus to sense a magnetic field includes a thin single domain ferromagnetic film magnetized in a predetermined direction known as the easy axis of the film, the magnetization of the film upon placement in an external magnetic field to be tested assumes a different direction which is the resultant field vector of the film's easy axis and the tested field axis, means to cyclically change the resultant magnetic field axis of the film, sensing means to note the cyclical changes in the magnetic field of the film caused by the shift of the resultant magnetic field due to the means to cyclically change the resultant magnetic field axis, and the apparatus to indicate being connected to the sensing means to note the result of the cyclical changes in the film.
(1) Note. A thin film is defined as a ferromagnetic element formed so as to have its magnetic domains aligned in a predetermined direction. This is usually done by vapor depositing the film in a magnetic field. In the absence of an external field the magnetization vector or magnetic moment will be aligned with the preferred "easy axis" of magnetization of the film. The "hard axis" of the magnetization of the film is in an orthogonal direction to the "easy axis". A thin magnetic film so formed has uniaxial anisotropy.
SEE OR SEARCH THIS CLASS, SUBCLASS:
227, for plural separate magnetic tests.
228+, for means to create a magnetic test field and a magnetic sensor to sense the test field.
SEE OR SEARCH CLASS
257, Active Solid-State Devices (e.g., Transistors, Solid-State Diodes), appropriate subclasses, including
108, 414, and 421-427, for devices responsive to magnetic field. 307, Electrical Transmission or Interconnection Systems,
403, for nonlinear reactor systems having thin film parametron.
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,
567, for miscellaneous thin film circuits.
365, Static Information Storage and Retrieval,
171+, for thin film magnetic signal storage systems.
427, Coating Processes,
547+, for pretreatment of a substrate or post-treatment of a coated substrate using magnetic field or force, 598+ to directly apply a coating using magnetic field or force.
