What is remanence (Br)?
Remanence (Br) is the amount of magnetism remaining in a material after an external magnetic field has been removed. It is an important property of permanent magnets and partly determines how strong a magnet can be.
When a magnet is produced, the material is exposed to a very strong external magnetic field. During this process, the magnetic domains within the material largely align in the same direction. This creates the permanent magnetization characteristic of a permanent magnet.
When the external magnetic field is then removed, a large part of this magnetization remains. The amount of magnetic flux density that remains is called remanence.
Remanence is often denoted by the symbol Br and is one of the most important properties of a permanent magnet material.
What does remanence mean?
Remanence describes how much magnetism remains in a material after the magnetizing field has been removed.
In other words, it indicates how strongly a material remains magnetic without external influence.
A material with high remanence can produce a more powerful magnetic field than a material with lower remanence.
Therefore, remanence plays an important role in the performance of permanent magnets.
Why is remanence important?
Remanence largely determines how much magnetic flux a magnet can deliver.
The higher the remanence, the greater the amount of magnetic energy available for applications such as:
- electric motors
- generators
- sensors
- loudspeakers
- industrial machinery
For designers and engineers, remanence is therefore an important parameter in the selection of magnetic materials.
How is remanence measured?
Remanence is expressed in:
- Tesla (T)
- milliTesla (mT)
- Gauss (G)
Most datasheets for neodymium magnets list a Br-value in Tesla.
Typical values for modern neodymium magnets often range between approximately:
1.0 and 1.5 Tesla
The exact value depends on the magnet grade used.
Remanence and magnet grade
One of the reasons why an N52 magnet is stronger than an N35 magnet is that the material has higher remanence.
This allows a larger magnetic field to be generated within the same volume.
However, this does not mean that remanence is the only determining factor for a magnet's performance.
Properties such as coercivity, dimensions, and temperature behavior also play an important role.
Remanence and the magnetic field
Remanence is sometimes confused with the field strength of a magnet.
Although both concepts are related, they describe different properties.
Remanence is a material property.
The actual field strength of a magnet is also influenced by:
- shape
- dimensions
- magnetization
- environment
Two magnets of the same material can therefore deliver different performances.
Remanence in the hysteresis curve
Within magnetic materials science, remanence is represented on the so-called hysteresis curve.
This graph shows how a material responds to magnetization and demagnetization.
The Br-value is read at the point where the external magnetic field has been reduced to zero.
Therefore, remanence is often considered a measure of a material's permanent magnetism.
Conclusion
Remanence, denoted by the symbol Br, describes how much magnetism remains in a material after the magnetizing field has been removed. It is one of the most important properties of permanent magnets and plays a significant role in the performance of neodymium magnets.
Materials with higher remanence can produce stronger magnetic fields and are therefore used in high-quality technical and industrial applications.
