Overview
IEC TR 62797:2013 documents an international intercomparison of magnetic moment measurements made with vibrating sample magnetometers (VSM) and superconducting quantum interference device (SQUID) magnetometers. The Technical Report summarizes results from participating research laboratories to assess the reproducibility of magnetic moment measurement methods. The exercise was coordinated by INRIM (Istituto Nazionale di Ricerca Metrologica) and Hannam University and supports the prospective development of a related IEC measuring standard.
Key technical topics and requirements
- Measurement methods compared: Vibrating Sample Magnetometer (VSM) and SQUID magnetometer techniques for determining magnetic moment and related magnetic parameters.
- Sample types: Hard ferrites (isotropic and anisotropic) and magnetic tape samples were used to evaluate performance across typical magnetic materials.
- Calibration and traceability: The report highlights the need for proper calibration (commonly using reference spheres) and laboratory traceability to ensure comparable results.
- Uncertainty evaluation: Participating laboratories were required to estimate measurement uncertainty in accordance with the ISO/IEC Guide to the Expression of Uncertainty in Measurement (GUM).
- Reproducibility assessment: The intercomparison provides data, tables and figures (see Annex A) showing dispersion and weighted uncertainties for quantities such as magnetic polarization, remanence, coercive field and maximum energy product.
- Practical considerations: The report discusses instrument sensitivity limits (e.g., applicability of VSM to hard magnetic materials and saturation magnetization for soft materials) and the role of measurement temperature.
Practical applications and users
This Technical Report is valuable for:
- Metrology and calibration laboratories conducting or validating magnetic moment measurements and seeking interlaboratory comparability.
- Research and development teams in magnetics and materials science evaluating hard magnetic materials (ferrites) or magnetic recording media (tape).
- Manufacturers and quality-control engineers who use VSM or SQUID systems for characterization and need guidance on uncertainty reporting and reproducibility.
- Standards developers preparing IEC measuring standards or updating test methods based on validated international data.
Practical benefits:
- Benchmarks reproducibility between VSM and SQUID instruments.
- Informs calibration best practices and uncertainty budgets.
- Supports selection of appropriate instrument type and measurement conditions for specific magnetic materials.
Related standards and documents
- ISO/IEC Guide: Guide to the expression of uncertainty in measurement (GUM) - used for uncertainty evaluation.
- ASTM A894/A894M - referenced as an existing standard related to saturation magnetization of nonmetallic magnetic materials.
- IEC measuring standards (prospective) - TR 62797:2013 provides empirical basis for future normative IEC standards on magnetic moment measurement.
For implementation, consult Annex A (results and analysis) and Annex B (participant list) in IEC TR 62797:2013 for detailed data and laboratory practices.