Ferromagnetic materials have following properties:

• In ferromagnetic materials, the magnetic lines of forces due to the applied magnetic field are strongly attracted towards the material.
• All ferromagnetic materials become paramagnetic above a temperature called Curie temperature

T_c

• Permeability is greater than 1.
• Magnetic susceptibility is large and positive.
• Magnetic susceptibility decreases with the rise in temperature according to Curie-Weiss law.
• Ferromagnetism is the  property of a material to be strongly attracted to a magnetic field and to become a powerful magnet.
• The source of ferromagnetism is the spin of the electrons.
• Ferromagnetic materials like Fe, Co, Ni, have incomplete inner shells. These shells can be completed by using Hund’s rule.
• When the specimen of a ferromagnetic material is magnetized by gradually increasing the magnetising fields, then the change of magnetic flux through the material is not continuous but in small discrete steps. Along the steep portion of the M-H magnetization curve, the discontinuous rotation of the magnetic domains give rise to Barkhauszen effect.

Reference: This article is referred from my book “electrical engineering materials” having ISBN 978-81-272-5069-0