Magnetic field sensor

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 (R1) coinciding with the direction in which magnetic flux is offered to the multilayer structure during operation, and a second in-plane reference axis (R2) which is perpendicular to the first reference axis (R1), whereby the magnetic easy axis (E1) of the first magnetic layer (1) is canted through an acute in-plane angle alpha with respect to the second reference axis (R2), and the magnetic easy axis (E2) 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 (R2). 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.