The Companion Guideuide to the Revised Technical Guidelines for Reliable DC Measurements of the Quantized Hall Resistance for Graphene-Based Devices has been published. Its goal is to support the international metrology community in the adoption of graphene-based quantum electrical resistance standards, contributing to the global effort towards their formal acceptance as reliable primary standards for the realisation of the ohm within the International System of Units.
The guide was developed by the CCEM Task Group on Graphene QHR Standards of the Consultative Committee for Electricity and Magnetism (CCEM) of the International Committee for Weights and Measures (CIPM) and is available in open access through the journal Metrologia under the Guides, Standards and Conventions section.
INRiM, which is part of the group with two researchers, contributed in particular to the section that developed the measurement of the Hall effect with current-comparator resistance bridges.
The guide revises and expands previous technical recommendations originally developed for gallium arsenide devices by addressing the specific characteristics of epitaxial graphene. Owing to their less demanding operating conditions, graphene-based systems can be implemented using more compact and cost-effective cryomagnetic platforms, facilitating wider access to primary quantum resistance standards for National Metrology Institutes and calibration laboratories.
The document provides practical guidance on device selection and characterisation, cooling and handling procedures, contact resistance management, and verification of the conditions required for observing the quantum Hall effect.