Given Curie constant and for sublattice 1 and 2.
Given
Now we consider antiparallel interaction between sublattice 1 and 2. Then from Curie law for each sublattice we can write
This is called ferrimagnetic interaction. We can write this equations as
These equations have a nonzero solution for and in zero applied field if
from this we get the transition temperature
For non zero applied field we solve the previous two equations and we get solutions for and . Which are given by
Now magnetic susceptibility
Where
This proves the result.
Since antiferromagnet is a special case of ferrimagnet. Then
Then we get
This proves the result.
Consider a ferrimagnet with two inequivalent sublattices such that the molecular fields B1 and B2 on...