Industrial experience with a quantized Hall effect system

In an effort to create the capability for the primary calibration of standard resistors traceable to physical constants, a measuring system based on the quantized Hall effect was assembled at Lockheed Missiles and Space Co. during the fall of 1989. Preliminary studies have been performed using three different samples of modulation-doped GaAs-(AlGa)As heterojunctions prepared by beam epitaxy techniques. The results of studies performed with one of these samples at the n=4 plateau are reported. These measurements were compared to results on a 10-k Omega primary resistor whose value is directly traceable to the US National Institute of Standards and Technology.<>