Deriving Relations for Specific Heats and Susceptibilities of Magnets

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SUMMARY

The forum discussion focuses on deriving specific relations for heats and susceptibilities of magnets as presented in Birger Bergerson's textbook on Equilibrium Statistical Mechanics. The key equations discussed include C_H - C_M = (T/χ_T) (∂M/∂T)_H² and χ_T - χ_S = (T/C_H) (∂M/∂T)_H², with a clarification that the term T is redundant in the susceptibility relation. The user identifies a potential typo in the textbook and seeks confirmation on the correctness of their derivation and its recognition in existing literature.

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Homework Statement


This question is from Birger Bergerson's textbook on Equilibrium Statistical mechanics.

Derive the relations
C_H-C_M = \frac{T}{\chi_T} \bigg(\frac{\partial M}{\partial T}\bigg)^2_H
\chi_T-\chi_S= \frac{T}{C_H} \bigg( \frac{\partial M}{\partial T}\bigg)^2_H
\frac{\chi_T}{\chi_S} = \frac{C_H}{C_M}

Homework Equations


C_X = T \bigg( \frac{\partial S}{\partial T} \bigg)_X
\chi_Y = T \bigg( \frac{\partial M}{\partial H} \bigg)_Y

Maxwell relations:
\bigg(\frac{\partial S}{\partial H}\bigg)_T = \bigg(\frac{\partial M}{\partial T}\bigg)_H

Chain rule:
\bigg(\frac{\partial S}{\partial T}\bigg)_H = \bigg(\frac{\partial S}{\partial T}\bigg)_M + \bigg(\frac{\partial S}{\partial M}\bigg)_T \bigg(\frac{\partial M}{\partial T}\bigg)_H

The Attempt at a Solution


For the first relation I get ##T^2## instead of ##T##, I'll write my solution:

C_H-C_M = T\bigg(\bigg(\frac{\partial S}{\partial T}\bigg)_H - \bigg(\frac{\partial S}{\partial T}\bigg)_M \bigg)=T\bigg(\frac{\partial S}{\partial M}\bigg)_T \bigg(\frac{\partial M}{\partial T}\bigg)_H

Notice that ##\bigg(\frac{\partial S}{\partial M}\bigg)_T = \bigg(\frac{\partial S}{\partial H}\bigg)_T \bigg(\frac{\partial M}{\partial H}\bigg)^{-1}_T = \bigg(\frac{\partial M}{\partial T}\bigg)_H \frac{T}{\chi_T}##, so if I plug the last relation to the relation above for ##C_H-C_M## I get ##C_H-C_M = \bigg( T^2/\chi_T \bigg) \bigg(\frac{\partial M}{\partial T}\bigg)^2_H##.

Am I right?

It seems this is a typo (if I am correct also appears in the third edition of this textbook).

Am I right?

Is this result known in the literature?

Have I missed something here?

Thanks.
 
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Never mind, I see that the mistake is in the susceptibility, the ##T## is redundant there.

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