Magnetic susceptibility

A measure of the degree to which a substance is attracted to a magnet [which is expressed by] the ratio of the intensity of magnetization to the magnetic field strength in a magnetic circuit.

Source:Service de « Travaux publics et Services gouvernementaux Canada »

Formula

{\vec M}=\chi _{m}\cdot {\vec H} where M is the magnetization in ampere by metre, \chi _{m} the magnetic susceptibility and H the magnetic excitation in ampere by meter.

If \chi _{m} > 0 : the body is paramagnetic ; if \chi _{m} <0 : the body is diamagnetic.