Magnetic Susceptibility

Magnetic susceptibility, k, is a measure of the ability of a material to be magnetized and is related to magnetic permeability (μ) by:

μ = μ_o (1 + k)

where μ₀ is the magnetic permeability of free space, which is 4π10^-7.  Ferromagnetic materials have the largest k and contain iron, nickel, cobalt and many of their alloys.   For example, magnetite is a ferromagnetic material with one of the highest magnetic susceptibility values. In environmental waste sites, the largest sources of magnetic anomalies are iron and steel.

The unit of magnetic susceptibility, k, in the SI system is dimensionless.  Magnetic permeability (μ) has units of Henrys per meter.  The geomagnetic field (B) has units of force per magnetic pole or Teslas.  The practical unit of geomagnetism is the nanotesla (nT), or gamma.  Most environmental magnetic surveys are measured in nT.