National Physical Laboratory

Magnetically hard materials: demagnetisation curve, remanence, intrinsic coercivity, maximum energy product

Magnetically hard materials

The remanence, coercivity, maximum energy product and demagnetisation curve of a range of magnetically hard materials can be determined in accordance with IEC 60404 Part 3: 1995.

  • Conventional metal magnets, e.g. alnico and alcomax
  • Ferrites
  • Cobalt platinum
  • Rare earth cobalt
  • Neodymium iron boron

The magnetic moment of permanent magnets is being used for 100 % quality control when the magnets are used in safety critical situations. The measurement method is electrical and the calibration of the individual instruments would be costly and often not convenient. A reference magnet can therefore be calibrated at NPL and this is used to provide a daily check of the calibration of customer systems.

A pulse magnetise is available that can achieve a peak magnetic flux density of approximately 8 T. Calibration of instruments that are used to measure magnetic fields with this type of time profile can be calibrated using this system.


Customer Service tel: +44 20 8943 8681

Last Updated: 18 Aug 2015
Created: 13 Aug 2007


Please note that the information will not be divulged to third parties, or used without your permission