A study of quantum Hall devices with different working magnetic fields for primary resistance metrology

Two kinds of quantum Hall devices with different working magnetic fields are fabricated and compared with the LEP (Laboratoires d'Electronique Philips) device, which is currently used in the primary resistance standard system of the National Institute of Metrology (NIM) of China. The comparison is made by calibrating the same 1 Ω standard resistor made by the National Measurement Laboratory of Australia using a Tinsley 100 Ω resistor as the intermediate standard and a cryogenic current comparator. The calibrated values from the NIM device with high working magnetic field and those from the LEP device agreed to within  −0.69  ×  10−9 with an uncertainty of 4.9  ×  10−9. The values from the NIM device with low working magnetic field and those from BIPM-2 agreed to within 2.5  ×  10−9 with an uncertainty of 7.1  ×  10−9.