Temperature Dependence of Magnetoresistance in Ni-Fe/Cu Multilayers

Ni x Fe 1-x /Cu multilayer films were prepared on glass substrate by magnetron sputtering. The dependence of the giant magnetoresistance on the composition and temperature were investigated. When the composition of the magnetic layer was varied, the MR ratio exhibited peaks at x=0.6 to 0.7 at 4.2K, and at x=0.7 to 0.8 at 300K. As the temperature was raised, the MR ratio of multilayer films with larger magnetic moments decreased more rapidly than that of films with lower magnetic moments. This result can be explained consistently in terms of the spin fluctuation model proposed by Hasegawa.