U.S. Philips Corporation

Jacques C Kools

Reinder Coehoorn

Martinus A Gijs

Wiepke Folkerts

Jacobus J Ruigrok

Josef P Naus

The device comprises a Wheatstone bridge with at least four magnetoresistive elements (1a, 1b, 1c, 1d) on a substrate (15), each magnetoresistive element comprising at least one sensitive portion (13) comprising successively a first ferromagnetic layer (19) having a magnetic easy axis (27) extending in a first direction, a non-magnetic layer (21) and a second ferromagnetic layer (23) having a magnetic easy axis (29) extending in a second direction that is different from the first direction. The sensitive portions (13) have mutually parallel sensitive directions that are parallel to a third direction (X). Each magnetoresistive element (1a, 1b, 1c, 1d) is associated with a current conductor (35a, 35b, 35c, 35d) provided in the immediate vicinity of that magnetoresistive element. The first direction (27) is canted through an acute angle with respect to the third direction (X), and the second direction (29) is canted in the opposite sense through an acute angle with respect to the third direction. Each one of the current conductors (35a, 35b, 35c, 35d) extends over at least a portion of its length in a fourth direction (Y) perpendicular to the third direction (X).

Device for detecting a magnetic field

A device for detecting a magnetic field, which device comprises a magneto-resistive multilayer structure comprising a first magnetic layer (1) which is separated from a second magnetic layer by an interposed non-magnetic layer, the multilayer structure having a first in-plane reference axis (R.sub.1) coinciding with the direction in which magnetic flux is offered to the multilayer structure during operation, and a second in-plane reference axis (R.sub.2) which is perpendicular to the first reference axis (R.sub.1), whereby the magnetic easy axis (E.sub.1) of the first magnetic layer (1) is canted through an acute in-plane angle .alpha. with respect to the second reference axis (R.sub.2), and the magnetic easy axis (E.sub.2) of the second magnetic layer is canted in the opposite sense through an acute in-plane angle .beta. with respect to the second reference axis (R.sub.2). Such a device lends itself to application in a magnetic head, for sensitive retrieval of magnetically-encoded data from a carrier in the form of a tape, disc or card.

Magnetic field sensor

A device for determining the orientation of a vehicle includes a magnetic field sensor (3) which is arranged in the vicinity of a ferromagnetic outer wall of the body of the vehicle and which is rigidly connected to the wall. External magnetic fields could unpredictably magnetize the wall portion (1) of the body, in the vicinity of which the magnetic field sensor (3) is provided, so that the measurements would become inaccurate. In order to achieve a substantial reduction of these adverse effects of external magnetic fields, the relevant wall portion is magnetically stabilized, preferably by including it in a magnetic circuit which also includes at least a magnet (11; 23, 27). The magnetic circuit preferably comprises also a yoke (23, 25) which has an approximately U-shaped cross-section and which is made of a soft magnetic material, the free ends of limbs (25) of the yoke facing the relevant wall portion (1) and the yoke being at least partly enclosed by an electric coil (27) in order to form an electromagnet.

Growing community of inventors

Eindhoven, Netherlands

Jacques C Kools