Question

Explain the following with suitable examples:
(i) Ferromagnetism
(ii) Paramagnetism
(iii) Ferrimagnetism
(iv) Antiferromagnetism

Answer 1

(i) Ferromagnetism
Certain substances exhibit very strong magnetic property. They can be permenently magnetised. They contain large number of unpaired electrons and the magnetic moment associated with it are equal in magnitude and aligned in the same direction.
Examples: Iron, cobalt, nickel, gadolinium, $Cr{O}_2$ etc.
(ii) Paramagnetism
When unpaired electrons revolve in the orbitals, a net magnetic field is associated with the substance containing these unpaired electrons.
Due to presence of unpaired electrons, certain substances experiences pull in magnetic field. The number of unpaired electrons determine the extent of paramagnetism.
Examples : Oxygen, $C{u}^{2+}$, $F{e}^{3+}$ and $C{r}^{3+}$

(iii) Ferrimagnetism
Unequal magnitude of magnetic moment associated with unpaired electrons are aligned in the same directions, the net magnetic moment is not zero.
Example: Ferrite $F{e}_2{O}_3$
(iv) Antiferromagnetism
Equal magnitude of magnetic moment associated with unpaired electrons are aligned in opposite directions, the net magnetic moment is zero.
Example: MnO, $M{n}_2{O}_3$ and $Mn{O}_2$