Anisotropic Magnets

In the production process, a preferred direction is effected to anisotropic magnets by using an external magnetic field. In a subsequent magnetizing process, the maximum magnetic values are obtained in this direction.

Coercive Field Force Hc

There is a distinction between the coercive field force BHc, the flux density, and the coercive field force IHc of the polarization. The coercive field force BHc (in the case of the closed magnetic circle) is defined as demagnetized field strength required for the removal of the flux density B. The coercive field force IHc is the demagnetized field strength whereby the polarisation becomes zero. Thus, by applying IHc, a body becomes non-magnetic. Practically speaking, all materials with high permeability are magnetic, mainly iron, nickel, cobalt, and related alloys. All other materials are non-magnetic (brass, copper, wood, stone, etc.).

Demagnetizing Curve

Part of the hysteresis loop within the second quadrant of the coordinate system (B respectively M positive, H negative). By measuring the demagnetizing curve, the most important magnetic features are determined.

Flux Density (magnetic) B

Describes the strength of the magnetic field as H does. Whereas outside magnetizable matter, B and H differ only by a constant factor, B accounts for the influence of the magnetization within such materials.

Unit: 1 Vs/m² = Wb/m² = 104 G = 1 T
Most common are the units
1 T = 104 G and 1 mT = 10 G

Gauss

The former common unit of the magnetic flux density.

Isotropic Magnets

Isotropic magnets may be magnetized in all directions with the identical magnetic features.

Magnetizing

Process of aligning the elementary magnetic areas by an external magnetic field.

Maxwell

Former unit for the magnetic flux.

Oersted

Former unit for magnetic field strength.

Remanence Br

Remanence is the induction (flux density) remaining in a ferrous magnetic material after removal of the magnetizing field. The numerical value of the remanence applies as a material constant for the case of the closed circle (H = 0) and is called true remanence (Br). In the opened magnetic circuit Br drops to the value of the apparent remanence Br.

Saturation Magnetizing

A magnetization, which can maximally be achieved by parallel alignment of all magnetic moments, is called saturation magnetization.

Sintered Magnet

Permanent magnet pressed from a mixture of magnetizable powders and hardened by heating in a vacuum.

Tesla

Unit for the magnetic Flux.
1 Tesla (T)= 104 G = 1 Vs/m2

Temperature Coefficient

Indicates the temperature dependency of the magnetic material's characteristic data Br and BHc. The temperature coefficients for Br, respectively BHc differ.

Weber

Unit for the magnetic Flux.
1 weber (Wb) = 1 Vs = 108 Maxwell