Patent ID: 6580270
Filing Date: 2003-06-17
Classification: B82Y,G01R,G11B,G11C

Abstract:
A device comprising an elongated field-sensitive ferromagnetic layer (1, 2, 3) of which the magnetization is sensitive to an applied field, said field-sensitive ferromagnetic layer comprising a sandwich structure comprising two magnetic layers (1, 2), the two magnetic layers having parallel easy magnetization axes and being coupled anti-ferromagnetically by a non-magnetic layer 3 separating the two layers the two layers 1 and 2, easy magnetization directions (M1, M2) for the two magnetic layers (1, 2) being directed substantially transversely to a longitudinal axis (I) of the field-sensitive ferromagnetic layer;the parallel easy magnetization axes are due to magnetocrystalline anisotropy and wherein opposite magnetization directions are present in the magnetic layers due to the anti-ferromagnetic coupling by the non-magnetic layer; and wherein the field-sensitive ferromagnetic layer forms the second layer of a first (6) and a second layer (1, 2, 3) of ferromagnetic material separated by a separation layer of non-ferromagnetic material (Ls, 7), the first and second layer being formed such that the magnetization (Mp) of the first ferromagnetic layer (6) is maintained in a fixed (pinner) direction in the presence of an applied magnetic field, while the magnetization direction of the second ferromagnetic layer (1, 2, 3) is able to change in the presence of an applied magnetic field, the device comprising means for directing a sensing current (Isense) through the elongated field-sensitive ferromagnetic layer in a current direction parallel to the longitudinal axis (I) or perpendicular to the plane of the layers.