A measure of the ability of a substance to sustain a magnetic field, equal to the ratio between magnetic flux density and magnetic field strength. For a vacuum, its value is 1.257 × 10−6 henries per meter. Highly magnetizable materials, such as ferromagnetic materials, have higher magnetic permeability.
The degree of magnetization of a substance in a given magnetic field, equal to the ratio of magnetic flux density to magnetic field strength.
The total magnetic induction or flux corresponds to the current of electricity (practically measured in amperes); the induction or flux density B to the density of the current (number of amperes to the square centimetre of section); the magnetic permeability to the specific electric conductivity; and the line integral of the magnetic force, sometimes called the magnetomotive force, to the electro-motive force in the circuit.
Coupling together these ideas he was finally enabled to prove that the propagation of electric and magnetic force takes place through space with a certain velocity determined by the dielectric constant and the magnetic permeability of the medium.
If we imagine the current in the conductor to be instantaneously reversed in direction, the magnetic force surrounding it would not be instantly reversed everywhere in direction, but the reversal would be propagated outwards through space with a certain velocity which Maxwell showed was inversely as the square root of the product of the magnetic permeability and the dielectric constant or specific inductive capacity of the medium.
Ni Resist can exhibit low levels of magnetic permeability i.e. they can be non magnetic.