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ShayanJ

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## Main Question or Discussion Point

According to Curie-Weiss law, the magnetic susceptibility obeys the equation [itex] \chi=\frac{C}{T-T_c} [/itex] where [itex] T_c [/itex] is the Curie temperature. People say this implies that the material is ferromagnetic for [itex] T<T_c [/itex],i.e. has non-zero magnetization in the absence of external magnetic field and then loses this property for [itex] T>T_c [/itex]. I have 2 questions now:

1) What is the domain of applicability of the mentioned equation?

2) A material is ferromagnetic if [itex] \chi \to \infty [/itex]. But the mentioned equation says that this only happens for [itex] T\to T_c [/itex] and below and above [itex] T_c [/itex], there is no ferromagneticity for the material. But in all references, it is said that below [itex] T_c [/itex] there is ferromagneticisty for the material. How can I solve this contradiction?

Thanks

1) What is the domain of applicability of the mentioned equation?

2) A material is ferromagnetic if [itex] \chi \to \infty [/itex]. But the mentioned equation says that this only happens for [itex] T\to T_c [/itex] and below and above [itex] T_c [/itex], there is no ferromagneticity for the material. But in all references, it is said that below [itex] T_c [/itex] there is ferromagneticisty for the material. How can I solve this contradiction?

Thanks