Permanent and Induced Magnets

Magnets can either be permanent or induced.

Magnets can be categorised into two types:

1. Magnetically soft materials:

  • Lose their magnetism very quickly
  • Can only be temporarily magnetised
  • Examples include nickel and iron

2. Magnetically hard materials

  • Retain their magnetism over a longer period
  • Can be permanently magnetised
  • Examples include steel

Permanent Magnets

Permanent magnets are magnets which always create their own magnetic field. Their magnetism cannot be turned on and off. So, they are always exerting a force on other magnets or magnetic materials.

  • When referring to magnets, such as common bar magnets or horseshoe magnets, we are talking about permanent magnets.

A permanent magnet can attract or repel another permanent magnet. However, it can only attract magnetic materials.

Induced Magnets

Induced magnets, also known as temporary magnets, become magnetized when placed in a magnetic field. However, induced magnets are only attracted to other magnets; they cannot repel them.

  • For example, iron filings become induced magnets when they are near bar magnets.

  • When the magnetic field is taken away, induced magnets lose most or all their magnetism.
  • When induced and permanent magnets are near each other, there is always an attraction.