List-Magnetik's Magnetic permeability meters

Low magnetism - permeability and remanence

The magnetic permeability is an indication of how strongly a material can be magnetized. The statement makes sense where no magnetism is actually desired, for example with stainless steel.

Magnetic permeability should not be confused with remanence or residual magnetism: Remanence says how strongly an object is really magnetized, permeability says how easily it could be magnetized, its ability to adapt to a magnetic field, so to speak.

Unit of permeability

The permeability μ is the ratio of the magnetic flux density B to the magnetic field strength H.

The relative permeability µr is the quotient of µ and the magnetic field constant µ0.

Measuring ranges of permeability measuring devices – paramagnetism

Magnetic materials can be classified based on their permeability number.

Diamagnetic substances 0 < µr < 1
Paramagnetic substances μr > 1
Ferromagnetic substances μr ≫ 1

Measurements with the permeability measuring devices from List-Magnetik can only be carried out on paramagnetic substances. For example, paramagnetic are aluminum, chrome, platinum, and stainless steel. In the case of stainless steel, the value µr depends on the alloy.

Ferromagnetic substances (iron, nickel, cobalt and various alloys) have a permeability number that is significantly greater than 1 and can assume values of more than 100. Such substances considerably increase the magnetic flux density of a magnetic field. List-Magnetik permeability measuring devices are not designed for this.

Limits of accuracy in permeability measurement

The measured value of the permeability depends on the dimensions of small samples. The sensitivity of the device increases with the thickness of the sample.
From a sample thickness of approx. 5 mm and a lateral dimension of approx. 2 cm, the measurement is independent of the size.
The approximate dependence of the sensitivity on the sample thickness is shown in the diagram.
The sensitivity is calculated as (µr displayed - 1) / (µr true - 1)

Calibration standard / calibration sample - an important accessory for the permeability meter

You can use the calibration standard supplied with the device to check the accuracy of the measurement at any time. The standard calibration standard has a value of µr ~ 1.35. Additionally offered calibration standards with reference values of µr ~ 1.03 and µr ~ 1.11 are available.