BAD METALS MADE WITH GOOD-METAL COMPONENTS

We have grown thin stable films of a good metal, Ag, that have charact eristics of bad metals: high resistivity, strong temperature dependenc e of resistivity, and lack of resistive saturation. For films of diffe rent thickness. the temperature-dependent resistance and the Hall effe ct resistance provide evidence that the apparent bad metallicity is a consequence of the microstructure of the film rather than the result o f new physics. This microstructure, which we characterize with scannin g probe techniques, occurs on length scales comparable to the mean fre e path, thereby changing the sign of the classical magnetoresistance f rom positive to negative, [S0031-9007(98)07453-5].