(i) Ferromagnetism: Ferromagnetic substances are those substance which are strongly attracted by external magnetic fielding, e.g., (iron, cobalt, nickle and CrO2 , etc.] Ferromagnetism arises due to spontaneous alignment of magnetic moments in the same direction.
Alignment of magnetic moments in ferromagnetic substance
(ii) Paramagnetism: Paramagnetic substances are those substances which are weakly attracted by magnetic field. It is due to the presence of one or more unpaired electrons, e.g.,O2 , Fe3+ , Cr3+ ,etc.
(iii) Ferrimagnetism: Ferrimagnetism is observed when the magnetic moments of the domains in the substance are aligned in parallel and antiparallel directions in unequal number resulting in some net magnetic moment, e.g., Fe3O4 (magnetite) and ferrites like MgFe2O4 , etc.
