TEMPERATURE-DEPENDENCE OF THE GIANT MAGNETORESISTANCE IN NI-CO/CU, NI-FE/CU, AND CO-FE/CU MULTILAYER FILMS

The temperature dependence of the giant magnetoresistance (GMR) of NixCo100-x/Cu (x=0, 30, 50, 70, 80, 90, and 100), NiyFe100-y/Cu (y=0, 40, 60, 80, and 90), and Co82Fe18/Cu multilayer films was investigated in the temperature range between 4.2 and 290 K. Samples were prepared by magnetron sputtering on a glass substrate. The oscillation of the MR ratio as a function of Cu thickness was observed in all the multilayers examined. The temperature dependence of the MR ratio was measured for the samples at the first and the second peak in the oscillation. The MR ratio decreased with increasing temperature except for the Ni/Cu multilayer at the first peak. Its dependence was well explained by the theory proposed by Hasegawa. We discussed the role of the spin fluctuation for the reduction of GMR with increasing temperature. © 1995 The American Physical Society.