AC measurements of the quantized Hall resistance

The quantized Hall resistance R/sub H/(i), for i=2, 4 and 6 has been measured over the frequency range from dc to 3 kHz using a standard four terminal-pair impedance bridge. For the ith plateau we found that R/sub H/(i) depended linearly on the magnetic flux density B and quadratically on the frequency f. That is, the relative difference /spl Delta/R/sub H/(i,f)/R/sub H/(i) between the ac and dc values is consistent with the empirical relationship k(i)Bf/sup 2/, where k(i) is constant. Below 3 kHz k(i) decreases by approximately a factor of six as i increases from 2 to 6. These results are consistent with inductances /spl ap/100 /spl mu/H, which depend on B, in series with each terminal of the quantum Hall device. From dc to 3 kHz we can derive the ac value of a standard resistor in terms of R/sub H/(2) with a type A relative uncertainty (1/spl sigma/) of 0.05/spl times/10/sup -6/ f/sup 2/ when f is expressed in kHz.