Physics of Magnetism

40 CHAPTER 4. THE MAGNETICALLY ORDERED STATE

In general, it is found that is almost temperature independent. This means that
reliable values of can also be derived in comparatively low fields for compounds
having a compensation point in their temperature dependence of the magnetization. When
measuring the field dependence of M at the latter temperature, one has
Eq. (4.4.20) applies already for low fields starting from the zero field. In fact, the presence
at the compensation temperature of two antiparallel sublattice moments of equal size leads
to a situation similar to that in an antiferromagnet below

and

One could then equally
well apply Eq. (4.3.27), where the intersublattice-molecular-field constant now takes
the form Magnetic dilution is another method to make the linear region given by
Eq. (4.4.20) fall into the experimentally available field range. In such a case, the larger of
the two sublattice magnetizations in Eq. (4.4.21) is reduced by substituting non-magnetic
atoms for the magnetic atoms on this sublattice.
Inelastic neutron scattering is another method to determine intersublattice-coupling
constants. This method is experimentally less easily accessible and will not be discussed