Low-magnetic-field magnetoresistive angle sensor

Abstract

Disclosed in the embodiments of the present invention is a low-magnetic-field magnetoresistive angle sensor. The sensor comprises: a substrate located in an X-Y plane, and a magnetoresistive sensing unit located on the substrate. The magnetoresistive sensing unit comprising a multi-layer thin film structure. The multi-layer thin film structure comprises at least a stack of a free layer, a barrier layer, and a reference layer. The magnetoresistive sensing unit has an oval shape. The oval-shaped free layer has a long axis Ly, a short axis Lx, and a thickness Lz. Additionally the free layer has a saturation magnetic field, a shape anisotropy demagnetizing field, and a magnetocrystalline anisotropy field in the X direction. When an external magnetic field rotates by 0-360° in the X-Y plane, the magnetocrystalline anisotropy field is compensated by the shape demagnetizing field to cause the effective anisotropy field of the free layer to be close to 0, such that the external magnetic field has a low working magnetic field value close to that of the saturation magnetic field of the free layer material. The embodiments of the present invention can improve the accuracy of angle measurement of a magnetoresistive angle sensor. Additionally because the required external magnetic field is low, the sensor can be implemented at low cost.

Dependencies are inferred from the claim text.