FERROMAGNETISM: The substances like iron,cobalt,nickel,gadolinium,chromium di oxide etc are strongly attracted by magnetic field.Such substances are called ferromagnetic substances.In solid state, the metal ions are grouped into small regions or DOMAINS,Which act as small magnet.When such substances are placed in a magnetic field,all the domains get oriented in the direction of the magnetic field, and a strong magnetic effect is produced.If the magnetic field is removed, the magnetic property persists.Thus, a permanent magnet is formed.This property ios called FERROMAGNETISM. PARAMAGNETISM: Some substances are weakly attracted by a magnetic field.Atoms of these substances have one or more unpaired electrons,which are attracted by the magnetic field.they are magnetised in the direction of the magnetic field.When the external magnetic field is removed,the magnetism is also lost.Thus, Paramagnetism is temporary.Examples of Paramagnetic substances are dioxygen,Cupric Cation,Ferric Cation etc. FERRIMAGNETISM: In ferrimagnetic substances, the net magnetic moment is small due to unequal number of magnetic moment of domains aligned in parellel and anti-parellel directions.these substances loose the ferrimagnetism on heating and become paramagnetic.Examples are:Ferrosoferric Oxide,MgFe2O4,Znfe2O4..etc. ANTIFERROMAGNETISM: These sbstances have domain structure similar to those of FERROMAGNETIC Substances,but their domains are oppositely oriented and cancel out each-other's magnetic mmoment.MnO is an antiferromagnetic substance.