Method for improving anisotropic magnetoresistance sensitivity by using surfactant

The invention discloses a method for improving anisotropic magnetoresistance sensitivity by using a surfactant, relating to the field of magnetic film materials. The method disclosed by the invention comprises the following steps of: sequentially depositing tantalum Ta (50-100A)/aluminium oxide Al2O3 (10-30A)/bismuth Bi (2-5A)/ferro-nickel Ni-Fe (70-120A)/bismuth Bi (2-5A)/aluminium oxide Al2O3 (10-30A)/tantalum Ta (50-100A) on a cleaned monocrystalline silicon substrate, and rapidly annealing at low temperature in a magnetic field. According to the invention, the surfactant Bi is intercalated in an interface between Al2O3 and NiFe, and the low-temperature and rapid annealing is carried out in the magnetic field, so that the saturation field of NiFe is obviously reduced, the sensitivity of the magnetic field is improved, and meanwhile the production cost is reduced; and the method disclosed by the invention is suitable for production of ultra-high sensitive magnetoresistance sensing elements in the future.