Theory:

Procedure to make a temporary magnet:
When an iron nail is kept near the steel pin on a wooden board, they do not attract each other. But by following the given procedure, we can make them to attract each other.
 
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Magnetising an iron nail
  1. Place one end (pole) of a bar magnet near one edge of the iron nail.
  2. Till you reach the other end, move the bar magnet along the length of the iron nail.
  3. Now, bring the pole to the starting point of the iron nail and move it in the same direction again.
  4. Note that the magnet is not swiped back and forth and must move in one direction alone.
  5. Repeat this process several times (around \(20\) to \(30\) times).
  6. Now, check whether the nail has become a magnet by placing a steel pin near the iron nail.
Observation:
The steel pins got attracted to the iron nail since the nail has become a temporary magnet. Hence, any magnetic material, such as a needle or a blade, can be converted into a temporary magnet.
Permanent magnets:
Permanent magnets are the magnets that maintain their magnetic property in the absence of an external magnetic field. Hardened steel and some alloys can produce permanent magnets. The most powerful and strongest magnets on Earth are Neodymium magnets.
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Hardened steel cylinders
Example:
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Refrigerator, speaker, and magnetic compass.
ALNICO:
An alloy of aluminium, nickel, and cobalt (ALNICO) helps make permanent magnets that are commonly used.
Uses:
While grazing, sometimes animals could have swallowed iron materials, which may cause damage or injuries to their digestive tract. In such situations, the Alnico cow magnet is used to remove those iron pieces by attracting the iron materials.
 
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Alnico cow magnet
Reference:
https://upload.wikimedia.org/wikipedia/commons/d/d2/CowMagnet.jpg