Material with a preferred direction of magnetisation that can not normally be changed after the material has been manufactured. Anisotropic magnets have a considerably higher energy product when compared to the isotropic version of the same material.


The direction through which a magnet is magnetised.


Maximum energy product indicates the highest energy obtained from a given permanent magnet material when operating at the optimum working point. In most applications, the strength of different materials is proportional to (BH)max. (KJ/m3 = 0.1256 MGOe).

Coercive Force

The negative field is required to reduce magnetic flux to zero after saturation. (1 A/m = 0.01256 Oe).

Coercivity Hc

The capability of a magnet to resist demagnetising fields. This is characterised by coercive force.

Curie Temperature

A temperature above which a magnet material ceases to have any ferromagnetic properties. This is much higher than the useful maximum operating temperature of a magnet.

Demagnetisation Curve

The second quadrant of the hysteresis loop after first being magnetised. Most magnets operate in this quadrant and therefore the curve contains information on the main magnet properties of a magnet.


Has no preferred direction of orientation and can therefore be magnetised in any direction.


A unit of magnetic flux density. (10,000 gauss = 1 tesla).


The maximum energy product of B & H at the working point on a normal bHc curve.  This is commonly used to designate varying grades of permanent magnet materials.


The end of a magnet which points to the geographical north, its correct title should be "north seeking pole".

Remanence, Br

Magnetic polarization of a magnet material in a closed circuit after saturation but with the external magnetising force removed. Remanence is measured in units of gauss or tesla, however, this must not be confused with the open circuit or surface gauss/tesla readings from a magnet which are normally considerably lower than remanence.

Temperature Coefficient of Br

Indicates the reversible decrease of remanence when subject to elevated temperatures. Usually shown as percentage change per unit of temperature.


Unit of magnetic flux density. (1 tesla = 10,000 gauss).

Working Point

The point on a demagnetisation curve at which the magnet functions. This is governed by temperature, operating conditions and the geometry of the magnet.