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:
- The spin alignment is in antiparallel manner as shown in Fig. 3.
- So net magnetic moment is zero.
- Susceptibility is small and positive, =C/(T+ T_N ).
- Initially susceptibility increases with increase in temperature and beyond Neel temperature (TN) the susceptibility decreases with temperature.
- At Neel temperature susceptibility is maximum.
- Examples: FeO, MnO, Cr2O3 and salts of transition elements.Fig. 1: Antiferromagnetic order.
Properties of Ferrimagnetic Materials:
- Ferrimagnetic material is a special type of antiferromagnetic material.
- The spin alignment is antiparallel but of different magnitudes as shown in Fig.4.
- So, they possess net magnetic moment.
- These materials are also called ferrites.
- Susceptibility is very large and positive for such materials.
- 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