Comparing Permeability and Remanence
Magnetic permeability should not be confused with remanence or residual magnetism: Remanence tells us how strongly an object is actually magnetized, permeability tells us how easily it could be magnetized.
Permeability
The relative permeability (µr) is a parameter that indicates how strongly a material can be magnetized. The value plays a particularly important role in stainless steels, where no magnetism is actually desired. Another term used for this is magnetic conductivity.
There is no unit of measurement, µr is dimensionless. Simple measuring devices examine the range between µr=1 (permeability of the vacuum) to 5. When measuring permeability, only weakly magnetic material can be measured due to technical limitations.
A measuring device for permeability in the range µr=1 to 5 is FerroPro compact.
Remanence or residual magnetism
Remanence is a special consideration of the magnetic field strength, the residual magnetic field strength remaining after the influence of a magnet or after a demagnetization process.
With all magnetic field measurements, it is important to remember that the earth itself has a magnetic field. Although it is very weak at 0.2 A/cm, this value will increase or decrease the measured value depending on the orientation of the probe. Therefore, deviations of 10% in the remanence range due to the earth's field are conceivable, and the position of the object and the position of the probe must be taken into account for the repeatability of a measurement.
The MP-80 is a measuring device for remanence in the range up to 100 A/cm.
