Fe$_{20}$Ni$_{80}$/Fe$_{50}$Mn$_{50}$ film magnetoresistive medium

The influence of several physico-technological factors on the microstructure and the magnetic and magnetoresistive properties of film structures based on Fe$_{20}$Ni$_{80}$/Fe$_{50}$Mn$_{50}$ bilayers with exchange (magnetic) bias is investigated. The dependences of the magnetic bias, coercive force, and anisotropic magnetoresistance on the deposition sequence and thickness of layers in the structures, substrate temperature, annealing temperature, and measurement temperature are determined for films obtained by magnetron sputtering, including with a high-frequency electric bias applied to the substrate. It is shown that the film SiO$_2$/Ta(5)/Fe$_{20}$Ni$_{80}$(5)/Fe$_{50}$Mn$_{50}$(20)/$_{20}$Ni$_{80}$(40)/Ta(5) structure offers an optimal combination of properties as a magnetoresistive medium with internal magnetic bias. Testing data for magnetic sensors made of this material by optical lithography are presented.