Patent ID: 7423847

Claim:
A magnetoresistive sensor capable of sensing external magnetic fields when a sense current is applied perpendicular to the planes of the layers in the sensor, the sensor comprising: a substrate; a stack of layers on the substrate and having a first edge for positioning near the magnetic field to be sensed and a second edge farther than the first edge from the magnetic field to be sensed, the stack comprising (a) a pinned ferromagnetic layer having an in-plane magnetization direction oriented generally orthogonal to said first edge; (b) a free ferromagnetic layer having an in-plane magnetization direction oriented substantially orthogonal to the magnetization direction of the pinned layer in the absence of an external magnetic field and substantially free to rotate in the presence of an external magnetic field; (c) an electrically conductive nonmagnetic spacer layer between the free ferromagnetic layer and the pinned layer; and (d) first and second insulating layers, each of the first and second insulating layers having one and only one generally rectangularly shaped aperture providing an electrically conductive path, wherein the length of the one and only one aperture in the first insulating layer is substantially non-parallel with the length of the one and only one aperture in the second insulating layer and wherein more than half the total of the area of both of the apertures is located closer to said first edge than to said second edge.