Effect of different buffer layers on the property of Ni₈₁Fe₁₉ thin films and microstructure analysis

Ta(NiFeCr)/NiFe/Ta films with Ta and NiFeCr buffer layers were prepared by magnetic sputtering. In comparison with Ta buffer layers the anisotropic magnetoresistance (AMR) values of the films with NiFeCr buffer layers increase dramatically for the same NiFe thickness. X-ray diffraction results show that the NiFeCr buffer layer promotes the formation of a stronger (111) texture in the NiFe films. High resolution transmission electron microscopy results show that the lattices of the NiFeCr buffer layer and the NiFe layer match well and the NiFe layer grows epitaxially along the direction of NiFeCr crystallites, so the films with NiFeCr buffer layers have a good crystal structure. After the films were annealed, the AMR values of the films with NiFeCr buffer layers keep constant when the temperature is below 350℃ and then decreases dramatically with a further increase of temperature. The films also have a good thermal stability after heat treatment at a temperature below 350℃.