Antiferromagnet and Ferrimagnet

ANTIFERROMAGNET AND FERRIMAGNET

Apart from diamagnetic, paramagnetic and ferromagnetic, there are also two more types of magnetic materials these are “Antiferromagnet” and “Ferrimagnet”.

Properties of Antiferromagnetic Materials:

1.  The spin alignment is in antiparallel manner as shown in Fig. 3.
2.  So net magnetic moment is zero.
3.  Susceptibility is small and positive, =C/(T+ T_N ).
4.  Initially susceptibility increases with increase in temperature and beyond Neel temperature (TN) the susceptibility decreases with temperature.
5.  At Neel temperature susceptibility is maximum.
6. Examples: FeO, MnO, Cr2O3 and salts of transition elements.Fig. 1: Antiferromagnetic order.

Properties of Ferrimagnetic Materials:

1.  Ferrimagnetic material is a special type of antiferromagnetic material.
2.  The spin alignment is antiparallel but of different magnitudes as shown in Fig.4.
3.  So, they possess net magnetic moment.
4.  These materials are also called ferrites.
5.  Susceptibility is very large and positive for such materials.
6. Examples: Ferrous ferrite, Nickel ferrite

Fig. 2 Ferrimagnetic order.

Also see (Click on these quick links) : 

1. Domain Theory of Ferromagnetism: http://www.askmattrab.com/notes/93-domain-theory-of-ferromagnetism

2. Antiferromagnetic and Ferrimagnet: http://www.askmattrab.com/notes/94-antiferromagnet-and-ferrimagnet

3. Magnetic Materials: http://www.askmattrab.com/notes/95-magnetic-materials

4. Working of the Transformer: http://www.askmattrab.com/notes/97-working-of-the-transformer