Giant Magnetoresistance Effect and Microstructure for Metallic Multilayers Ni₈₀Fe₂₀/Cu with Low Saturation Field

The Ni₈₀ Fe₂₀ /Cu_N multilayers with low saturation field and giant magnetoresistance effect have been successfully prepared by magnetron sputtering method.The oscillatory changes of its magnetoresistance and interlayer exchange coupling with copper thickness increasing have been observed at room temperature while saturation magnetoresistance values reach 19.4% and 11.7% and saturation fields are approximately 64000 A/m and 8 000 A/m when the Cu layer thickness equals 1 and 2.2 nm respectively.Saturation magnetoresistance values are 33.2% and 27.6% at low temperature(77K).Dependence of giant magnetoresistance on microstructure, including NiFe layer thickness and then number of period N, has been studied systematically. Changes in GMR characteristics have been observed after vacuum annealing.