Why Do Magnets Attract Iron?

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A refrigerator magnet sticks to steel.

It may do almost nothing to aluminum foil.

That is because magnets do not attract every metal.

Iron and certain other materials respond especially strongly to magnetic fields.

Iron contains magnetic domains

The atoms in iron have magnetic properties.

Within the material, groups of atoms can form regions called magnetic domains.

Inside each domain, many atomic magnetic effects are aligned.

In an unmagnetized piece of iron, different domains may point in different directions.

Their effects partly cancel one another.

The entire object therefore may show little overall magnetism.

Bring a strong magnet close and the external magnetic field encourages domains in the iron to line up more strongly with that field.

Now the iron itself becomes magnetized.

The side closest to the magnet develops a magnetic orientation that creates attraction.

This alignment is also the basic reason a compass needle responds to Earth’s magnetic field, although a compass uses a permanent small magnet rather than an ordinary piece of iron.

An unmagnetized piece of iron can rearrange its domains in response to whichever pole is nearby.

The closest side develops the appropriate opposite magnetic character.

So either the north or south end of a magnet can attract the iron.

Different materials have different electronic structures.

Iron, nickel, cobalt, and some alloys show strong ferromagnetic behavior.

Aluminum and copper respond far more weakly and do not behave like ordinary iron around a household magnet.

Sometimes.

Depending on the material and strength of the field, some domain alignment can remain after the original magnet is removed.

That is one way materials can become permanent magnets.

So magnets do not attract every shiny metal object.

Iron happens to have internal magnetic regions that can line up and join the game.

And that’s the short explanation.