By Curie-Weiss law , $$\chi_m = \frac{C}{T-T_c}$$ Where, C is Curie constant and $T_c$ is Curie temperature. If T = $T_c$ would then $\chi_m$ be $\infty$ ? But by theory , at Curie temperature the ferromagnetic material becomes paramagnetic. But , for a paramagnetic material, $$\chi_m\gt1$$ How is this possible?

Please point out and explain where am I going wrong.

  • $\begingroup$ It is true that the susceptibility diverges at the critical temperature. I am unsure where you got that $\chi_{m}<1$ for a paramagnet? $\endgroup$ Commented Dec 24, 2023 at 21:06
  • $\begingroup$ Oops! You are right. For paramagnetic materials magnetic susceptibility is not less than unity but its greater than unity. However in many of the textbooks its specified that $\chi_m$ is very small. For example water has susceptibility in the order of $10^{-7}$. $\endgroup$
    – Vinay5101
    Commented Dec 25, 2023 at 0:34
  • $\begingroup$ I am not aware of this either, as far as I know the definition of a paramagnet is that the susceptibility is $\chi_{m}>0$. $\endgroup$ Commented Dec 25, 2023 at 7:32


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