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CHAPTER 10. CALORIC EFFECTS IN MAGNETIC MATERIALS
In the absence of the magnetic field, the 2J + 1 energy states of each of the participating
N
magnetic moments are degenerate. For a system which contains non-interacting magnetic
moments, and therefore consists of
available states, we can easily calculate
the entropy. According to Boltzmann’s theory, the corresponding entropy is
As has been discussed in Section 3.1 and illustrated for the case
in Fig. 3.1.1,
application of a magnetic field will lift the degeneracy of each of the N manifolds of 2J + 1
states. It follows from Fig. 3.1.1, and also from Eq. (3.1.1), that the energy separation
between any two of the magnetically split 2J + 1 states equals
Let us suppose
that the temperature at which the system is magnetized by means of the field H is so low
that the thermal energy
is small compared to
In this case, only the lowest
state (m = –J) will be occupied for each of the N spins. The corresponding entropy is now
CHAPTER 10. CALORIC EFFECTS IN MAGNETIC MATERIALS
In the absence of the magnetic field, the 2J + 1 energy states of each of the participating
N
magnetic moments are degenerate. For a system which contains non-interacting magnetic
moments, and therefore consists of
available states, we can easily calculate
the entropy. According to Boltzmann’s theory, the corresponding entropy is
As has been discussed in Section 3.1 and illustrated for the case
in Fig. 3.1.1,
application of a magnetic field will lift the degeneracy of each of the N manifolds of 2J + 1
states. It follows from Fig. 3.1.1, and also from Eq. (3.1.1), that the energy separation
between any two of the magnetically split 2J + 1 states equals
Let us suppose
that the temperature at which the system is magnetized by means of the field H is so low
that the thermal energy
is small compared to
In this case, only the lowest
state (m = –J) will be occupied for each of the N spins. The corresponding entropy is now