High magnetoresistance in sputtered Permalloy thin films through growth on seed layers of (Ni0.81Fe0.19)1-xCrx

The use of thin (Ni_0.81Fe_0.19)_1-xCr_x seed layer for obtaining high anisotropic magnetoresistance in Permalloy (Ni_0.81Fe_0.19) films is reported. The process yields a high ΔR/R of for example, 3.2% for 120-Å-thick NiFe, without high-temperature deposition or annealing. X-ray diffraction shows that the NiFeCr seed layer causes the formation of large [111] textured grains in the Permalloy film, and that the interface between these two layers is quite smooth. These both increase the ΔR and reduce the resistance R in the film, which lead to the high ΔR/R. Also discussed is the enhanced ΔR/R and thermal stability trilayer magnetoresistive sensors using this NiFeCr instead of Ta as a spacer.