Self biased multilayer magnetoresistance sensor

A self-biased sensor comprising:

• a current source which produces a current;
• a sensor element having a longitudinal direction and a resistance that is sensitive to a magnetic field to be measured, said sensor element connected to said current source and receiving the current which passes through the sensor element to create a self-biasing field, said sensor element comprising,
• a first ferromagnetic layer having a magnetization direction which is sensitive to the magnetic field and, when not subject to the magnetic field, is oriented by the self-biasing field in a first direction perpendicular to the longitudinal direction,
• a first conductive, non-magnetic layer disposed on said first ferromagnetic layer,
• a second ferromagnetic layer disposed on said first conductive, non-magnetic layer and having a magnetization which is blocked and directed in the longitudinal direction,
• a second conductive, non-magnetic layer disposed on said second ferromagnetic layer, and
• a third ferromagnetic layer disposed on said second conductive, non-magnetic layer having a magnetization direction which is sensitive to the magnetic field and, when not subject to the magnetic field, is oriented by the self-biasing field in a second direction perpendicular to the longitudinal direction and substantially of an opposite sense to the magnetization of the first ferromagnetic layer;
• and
• a resistance measuring device which measures a resistance value of the sensor element that corresponds to the magnetic field to be measured.