Resistance Fluctuations in Multiprobe Microstructures: Length Dependence and Non-Locality.

We study numerically the resistance fluctuations, deltaR, in disordered metallic microstructures with two eight probes. In a particular four-probe structure, deltaR is independent of the voltage probe separation, L, for L less than a geometrically defined phase breaking length, in agreement with experiment. For other structures, deltaR shows a variety of length dependences which should be experimentally observable. Non-local fluctuations decay very slowly as the distance between the current path and voltage probes increases.