Low-frequency measurements of the quantized Hall resistance

Measurements of the quantised Hall resistance R/sub H/(i) for i=2 and 4 have been made over the frequency range 0.4-6.4 kHz using a modified ac bridge. The results have been corrected for cable effects and the frequency-dependence of the standard resistor R/sub s/. The measurements indicate that in addition to a linear frequency dependence f there is also a linear dependence on source-drain voltage V/sub SD/ such that: /spl Delta/R/sub H/(i)/R/sub s/=/spl alpha/[V/sub SD/+/spl nu/(i)]f where /spl alpha/(i) and /spl nu/(i) are constants.