Ferromagnetic Materials

Iron is oxidized to generate an oxide, which is then transformed into the ferromagnetic material known as magnetite. Curie temperature for it is 580 °C. It was recognized earlier as a magnetic material. Of all the naturally occurring minerals on Earth, magnetite possesses the strongest magnetic properties.

Properties of Ferromagnetic Materials

1. The atoms of ferromagnetic substances have permanent dipole moments present in domains.
2. Atomic dipoles in ferromagnetic substances are oriented in the same direction as the external magnetic field.
3. The magnetic dipole moment is large and is in the direction of the magnetising field.
4. The relative permeability is also very large and varies linearly with the magnetising field, and the field inside the material is much stronger than the magnetising field. They tend to pull in a large number of lines of force by the material.
5. Ferromagnetic substances are strongly attracted by the field. So, in a nonuniform field, they tend to stick at the poles where the field is strongest.
6. If a ferromagnetic powder is placed in a watch glass placed on two pole pieces which are sufficiently apart, then powder accumulates at the sides and shows depression in the middle because the field is strongest at poles.
7. When a ferromagnetic substance is liquefied, it loses ferromagnetic properties due to higher temperature.

Curie Temperature

Temperature affects ferromagnetic behavior. The transition from ferromagnetic to paramagnetic occurs at high enough temperatures. Curie's temperature is the temperature at which this transition happens. TC represents it.

Uses of Ferromagnetic Materials

There are wide applications of ferromagnetic materials in the industry. They are widely used in devices like electric motors, generators, transformers, telephones, loudspeakers, and magnetic stripes on the back of credit cards.