Overview of magnetic susceptibilities

The popular experimental techniques involve Faraday or Gouy balance measurements where the quantity being measured is the force acting on a body when it is in the magnetic field 

The work done in bringing the body of volume V with a uniform magnetisation M into a magnetic field is 

For isotropic non-ferromagnetic materials with volume susceptibility x it is d M = /d// 

When the sample is allowed to move in one direction (z) only, then one gets 

Evidently, the susceptibility subduced from such experiments is the mean mass susceptibility. This quantity, for linear magnetics, is close to the isothermal susceptibility. However, deviations from linear behaviour increase with 

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