Question

Define : Ferromagnetism

Hint:

At very high temperatures, ferromagnetic substances lose their permanent magnetism and become paramagnetic. The temperature at which this transition occurs is called the Curie temperature.

Answer 1

Step 1: Understanding the Concept:
Magnetic properties arise from the spin and orbital motion of electrons. In ferromagnetic materials, metal ions are grouped into small regions called domains.
Step 2: Detailed Explanation:
In an unmagnetized piece of ferromagnetic material, these domains are randomly oriented, and their magnetic moments cancel out.
When placed in an external magnetic field, all domains orient themselves in the direction of the magnetic field. This produces a strong magnetic effect.
The characteristic feature of ferromagnetism is that this ordering of domains persists even after the external magnetic field is removed, turning the substance into a permanent magnet.
Common examples include Iron (\( Fe \)), Cobalt (\( Co \)), and Nickel (\( Ni \)).
Step 3: Final Answer:
Ferromagnetism is the phenomenon of spontaneous and permanent alignment of magnetic domains in a substance, resulting in strong magnetic attraction.