What are the key features of a demagnetization curve?
The demagnetization curve is measured by first saturating the material (exposing it to enough magnetic field so that it is magnetically aligned) and then gradually decrease the magnetic field while constantly measuring the magnetic flux within the magnet. Once the field becomes negative (the reverse direction compared to the original saturating field) it begins to demagnetize the magnet and the available magnetic flux from it reduces. Eventually, no more flux is available and the magnet starts to remagnetize in the opposite direction. Schematically this looks like The horizontal axis is the strength of the magnetic field applied by the instrument, and the vertical axis is a measure of the magnetic flux in the magnet. The key magnetic parameters that are always extracted from this curve are • Br – the remanent induction, the measure of the magnetic flux density when there is no external magnetic field present • Hc – the coercivity, the magnetic field at which the induction switches dire
