On the basis of their behaviour in a magnetic field, the various materials can be classified in three classes.
(i) Diamagnetic: Those materials, which when placed in a magnetising field, are feebly magnetised in a direction opposite to the magnetising field are called diamagnetic substances. A few examples of diamagnetic materials are: copper, zinc, bismuth, water, sodium chloride, helium, argon etc.
When a diamagnetic substance is suspended in a magnetic field, it arranges itself in the direction of the magnetic field.
(ii) Paramagnetic: Those materials, which when placed in a magnetising field, are feebly magnetised in the direction of magnetic field, are called paramagnetic substances. A few examples of paramagnetic substances are: aluminium, sodium, antimony, platinum, copper chloride, liquid oxygen etc.
When a paramagnetic substance is suspended in a magnetic field it arranges itself to the direction of magnetic field.
(iii) Ferromagnetic: Those materials which when placed in a magnetising field are strongly magnetised in the direction of the magnetising field, are ferromagnetic substances. A few examples of ferromagnetic substances are iron, nickel, cobalt, alnico, mercury etc.
