Explain Properties of Ferromagnetic Substances

Ferromagnetic substances are those in which each atom or molecule has a strong spontaneous net magnetic moment. These substances exhibit strong paramagnetic properties.

  1. The susceptibility and relative permeability are very large. (For example: μr for iron = 200,000)
  2. Susceptibility is inversely proportional to the absolute temperature. (i.e) X α 1/T. As the temperature increases the value of susceptibility decreases. At a particular temperature, ferromagnetic become paramagnetic. This transition temperature is called Curie temperature. For example, Curie temperature of iron is about 1000 K.
  1. When suspended freely in the uniform magnetic field, they set themselves parallel to the direction of magnetic field.
  2. When placed in a non-uniform magnetic field, they have a tendency to move from the weaker part to the stronger part of the field. They get strongly magnetized in the direction of the field.

Examples: Fe, Ni, Co and a number of their alloys.