In order to understand the transport properties of multilayer systems, three different series of sputtered Fe/Cu multilayer films were examined by low-frequency ac resistance measurements. In each series, the total thickness of the film was maintained at approximately 2000 Å while the bilayer thickness was varied from 20 to 300 Å. The three multilayer series differ in the ratios of Fe to Cu in a bilayer. The Fe:Cu ratios examined here are 1:3, 1:1, and 3:1. Transport and magnetotransport measurements were done on these films at temperatures of 296, 77, and 4.2 K with in-plane fields up to 10 KOe. As expected, for each Fe:Cu series the resistivities increase with decreasing bilayer thickness. Furthermore, comparing the different series, the higher Cu ratios give smaller resistivities. From the magnetotransport measurements, the anisotropic magnetoresistance also increases with decreasing bilayer thickness and appears to be linearly related to the resistivity of the multilayer, especially at the lower temperatures. For the highest Cu ratio, Fe:Cu 1:3, the AMR was unmeasureable from the thinnest periods at 296 K but becomes significant at the lower temperatures.
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