COMPARISON OF QUANTUM HALL-EFFECT RESISTANCE STANDARDS OF THE BNM LCIE AND THE BIPM/

A comparison of quantum Hall effect (QHE) resistance standards has bee n carried out by taking a complete QHE system from the BIPM to the Lab oratoire Primaire d'Electricite-Magnetisme (BNM/LCIE). from December, 14-17, 1993, measurements of the same 100 Omega standard resistor were carried out in terms of the quantized Hall resistance (QHR) standards of the two laboratories. This exercise followed a preliminary compari son in July 1993 in which the ratio of the 100 Omega standard to a 1 O mega standard, and that of the 100 Omega standard to a 10 k Omega stan dard were measured at the BNM/LCIE using the resistance-ratio bridges of both laboratories. All comparison results agree to within 4 parts i n 10(9). In particular, the values attributed by the two laboratories to the 100 Omega standard, based on the mean of measurements made on t he i = 2 plateaus of GaAs-based heterostructures, agreed to (1.2 +/- 3 .0) parts in 10(9).