Comparison of quantum Hall effect resistance standards of the BNM/LCIE and the BIPM

A comparison of quantum Hall effect (QHE) resistance standards has been carried out by taking a complete QHE system from the BIPM to the Laboratoire Primaire d´Electricite-Magnetisme (BNM/LCIE). From December, 14-17, 1993, measurements of the same 100 Ω standard resistor were carried out in terms of the quantized Hall resistance (QHR) standards of the two laboratories. This exercise followed a preliminary comparison in July 1993 in which the ratio of the 100 Ω standard to a 1 Ω standard, and that of the 100 R standard to a 10 kΩ standard were measured at the BNM/LCIE using the resistance-ratio bridges of both laboratories. All comparison results agree to within 4 parts in 10⁹ . In particular, the values attributed by the two laboratories to the 100 R standard, based on the mean of measurements made on the i=2 plateaus of GaAs-based heterostructures, agreed to (1.2±3.0) parts in 10⁹