News

Unit of electrical resistance can be reproduced externally with unprecedented precision using the quantum Hall effect within EMRP project (SIB51 GraphOhm)

Project partners CMI, PTB, VTT, SP, METAS and collaborator UCT Prague have demonstrated the possibility of using the quantum Hall effect (QHE) to reproduce the unit of electrical resistance with an uncertainty below a few parts in 10^8. This was shown outside of NMIs and without an external supply of liquid helium. A commercially-available system with appropriate improvements for resistance metrology and low pick-up of noise was used.

A world-wide operating instrumentation manufacturer announced during the project's dissemination meeting in Prague his plans for marketing a dedicated commercial system of similar type. This EMRP project Quantum resistance metrology based on graphene will allow the full space of all electrical quantities to be spanned, when combined with the unit of electrical voltage, based on the Josephson effect. Following the forthcoming redefinition of the international system of units, the kilogram will also rely on the QHE and the Josephson effect for its reproduction.