Question

What happens above curie temperature ?

Answer 1

Hint:Magnetic susceptibility is the extent to which a substance can be magnetized in the presence of an external magnetic field. It is defined as the ratio of magnetic moment per unit volume i.e., magnetization to the applied magnetic field intensity. It is represented by $\chi $.

Complete answer:
Different substances can be classified into diamagnetic, paramagnetic and ferromagnetic on the basis of values of magnetic susceptibility. Let us discuss each type of magnetic behaviour as follows:

Diamagnetic substances: These substances show repulsion when placed in an external magnetic field that means the materials are anti-aligned and are forced to move towards the region of lower magnetic field. The value of magnetic susceptibility is very small and negative for these substances.

Paramagnetic substances: These substances are weakly magnetized in the presence of an external magnetic field that means the material gets aligned with the applied field and is attracted towards the region of greater magnetic field. The value of magnetic susceptibility is small and positive for these substances.

Ferromagnetic substances: These substances when placed in an external magnetic field get strongly magnetized that means these substances are strongly attracted to a magnet and tend to move from weak magnetic regions towards regions with greater magnetic field. The value of magnetic susceptibility is very large and positive for these substances.

Now, let’s discuss the magnetic properties of a substance above Curie temperature. Curie temperature: It is the minimum temperature at which the ferromagnetic property of a substance is converted into paramagnetic property i.e., above curie temperature, the ferromagnetic material tends to show paramagnetism. It is represented by ${T_C}$.

Therefore, we can conclude that above curie temperature, ferromagnetism of the substance vanishes and it gets converted into a paramagnetic substance.

Note:It is important to note that antiferromagnetic substances get transformed to paramagnetic substances at a minimum temperature which is known as Neel temperature and it is analogous to the Curie temperature. It is represented by ${T_N}$.