Temperature dependence of metrological characteristics of quantum Hall effect samples

Influence of temperature on frequency performance of an AlGaAs-GaAs heterostructure fabricated by Laboratoires d'Electronique Philips has been investigated. The structure was placed into a /sup 4/He bath and significant improvement of its frequency performance has been observed when the operational temperature was reduced from 4.2 K to 1.6 K. For T=1.6 K and I=30 /spl mu/A, an approximately linear frequency dependence of the quantized Hall resistance R/sub H/(2) was found, its slope being 0.11 ppm/kHz.