Ferrite Devices

Magnetically soft versus magnetically hard

What do we mean by "magnetically 'soft'"? Alloys useful for magnetic shielding are said to be magnetically "soft" because they can absorb magnetic energy without retaining it. Magnetically "hard" materials, on the other hand, make good magnets because they can retain a strong magnetic field even after the source of the magnetic energy has been removed. When a magnetic field is removed from a magnetic shield alloy, there is no remaining (residual) magnetic field. The measure of this property is called coercive force. For a magnetic shield, the lower the coercive force, the better.

Oersted: A unit (symbol Oe) of magnetic field strength. It is equal to a force of one dyne acting upon a unit magnetic pole in a vacuum.