GEOLOGY

Detailed explanation-1: -If a magnet is exposed to high temperatures, the delicate balance between temperature and the domains in a magnet are destabilized. At around 80 °C, a magnet will lose its magnetic force and it will become demagnetized permanently if exposed to this temperature for a period, or if heated above its Curie temperature.

Detailed explanation-2: -On coating a magnet with a layer of oil, the magnet does not lose its magnetism.

Detailed explanation-3: -Permanent magnets can lose their magnetism if they are dropped or banged on enough to bump their domains out of alignment. Heating a magnet above the Curie temperature causes the magnetic domains to be disrupted permanently. Mild heating causes a reduction in the magnetism.

Detailed explanation-4: -What can cause the realignment of magnetic domains in a material? Heat, a jarring impact, or moving a material relative to a magnet can cause realignment of magnetic domains.