What happens to a bar magnet when it is heated?

What happens to a bar magnet when it is heated?

Its polarity reverses
Its magnetism is increased
Its magnetism remains unchanged
Its magnetism is either reduced or lost
This question was previously asked in
UPSC Geoscientist – 2022
When a bar magnet is heated, the increased thermal energy causes the atoms within the magnetic material to vibrate more vigorously. This increased vibration disrupts the alignment of magnetic domains, leading to a reduction or complete loss of magnetism.
– There is a specific temperature, called the Curie temperature, above which a ferromagnetic material loses its ferromagnetism and becomes paramagnetic.
– Heating below the Curie temperature can still weaken the magnet’s field, especially if the magnet is not uniformly heated or has structural imperfections.
Heating is one way to demagnetize a magnet. Other methods include hammering or exposing it to a strong alternating magnetic field (as in a degausser). The loss of magnetism is due to the disorganization of the microscopic magnetic moments within the material.