Diamagnetic substances are those in which the individual atoms/ions/molecules do not possess any net magnetic moment of their own when they are placed in a strong magnetic field, they are repelled and align itself in a direction at right angle to field. Bismuth, copper, quartz, mercury are some of diamagnetic substances.
Paramagnetic substances are those in which each individual atom/ion/molecule has a net non-zero magnetic moment of its own. When placed in external magnetic field, it tries to align itself in the direction of the field.
Aluminium, platinum, chromium are few examples of paramagnetic substances.
Ferromagnetic substances are those in which each individual atom/molecule/ion has non-zero magnetic moment and when placed in magnetic field it spontaneously aligns itself towards magnetic field.
Iron, cobalt, nickel are some ferromagnetic substances.
