Permanent and Induced Magnets

Magnets can either be permanent or induced.

We can separate magnets into two categories:

1. Magnetically soft materials – Lose their magnetism very quickly – For example nickel and iron

  • Materials that can be permanently magnetised are magnetically hard.

2. Magnetically hard materials – Lose their magnetism slowly – For example steel

  • Materials that can only be temporarily magnetised are magnetically soft.

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, or temporary magnets, are magnetic materials which become magnets when they’re put into a magnetic field. However, the induced magnets can only be attracted to other magnets, not repelled.

  • For example, iron filings become induced magnets when they are near bar magnets.
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  • When the magnetic field is taken away, induced magnets lose most or all their magnetism.
  • When induced and permanent magnets come together, there is always an attraction.