Glossary of magnetic terminology
We have created a glossary to help professionals, researchers, and enthusiasts understand the complex terminology of magnets and magnetism.
Understanding the terminology is essential to grasp the characteristics of different magnets and their applications.
Remanence – Br (Gauss, Gs)
This is the point at which the hysteresis loop crosses the B-axis when the magnetizing force is zero. It represents the maximum magnetic flux output from the given magnetic material. By definition, this point occurs with a zero air gap, and therefore, it is not observable in the practical use of magnetic materials.i.
Coercive Force – Hcb (Oersted, Oe)
This is the demagnetizing force, measured in Oersted, required to reduce the magnetic induction B to zero after the magnet has been brought to saturation.
Intrinsic Coercive Force – Hcj (Oersted, Oe)
Measured in Oersted in the CGS system, this is a measure of the material’s intrinsic ability to resist demagnetization. It is the demagnetizing force required to reduce the intrinsic induction in the magnetic material to zero after it has been saturated.
Maximum Energy Product – Bhmax (Mega Gauss Oersted, MGOe)
This is the point on the demagnetization curve where the product of B and H is at its maximum. It represents the minimum volume of magnetic material needed to deliver a given energy to the surrounding environment.
The maximum energy product is measured in Mega Gauss Oersted (MGOe).
Demagnetization Curve
This refers to the second quadrant of the hysteresis loop, which generally describes the magnetic behavior in practical use. The demagnetization curve is also known as the B-H curve.
Curie Temperature – Tc
The Curie temperature is the temperature at which the parallel alignment of elemental magnetic moments completely disappears, and the material can no longer maintain magnetization.
Magnetic Flux, Ø
This refers to the total magnetic induction over a given area.
When the magnetic induction, B, is uniformly distributed over an area, A, then Ø = B × A.
The general equation is: Ø = ∫ B · dA
Permeance Coefficient
Pc: The ratio between magnetic induction, Bd, and its self-demagnetizing force, Hd.
Pc = Bd / Hd
The permeance coefficient is also known as the operating point or “load line” of the magnet. It is useful for analyzing the magnet’s external flux and estimating performance under various working conditions.
As an approximation:
Bd / Hd ≈ Lm / Lg,
where Lm is the length of the magnet and Lg is the length of the air gap the magnet is working across.
