Every atom in the periodic table has some magnetic properties, though for most, you'd find it hard to detect. The atom's electrons have a tiny magnetism of their own, but this magnetism cancels itself out for all but a few metallic elements. From these, you can make permanent magnets.
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Iron, a common metal, has strong magnetic properties. You can turn a certain kind of iron into a permanent magnet by exposing it to a brief, strong magnetic field. Natural magnetic rocks called lodestones contain iron crystals that became magnetised by a lightning strike. Another form of iron, called soft iron, won't take a permanent magnetic field, but you can make powerful electromagnets with it. Here, iron reinforces the magnetic field produced by electricity in a coil, but reverts to its former non-magnetic state when you turn the current off.
By itself, the metal cobalt has magnetic properties similar to iron, though cobalt's magnetism is weaker. Combined with other metals, such as in the alloy Alnico (aluminium-nickel-cobalt) or cobalt-samarium, the mixture has much stronger magnetism than the elements have by themselves.
You can attract bits of nickel to a magnet just as you can with cobalt and iron. Nickel's magnetism, like cobalt's, is weaker than iron's. Used in alloys, nickel can either strengthen or weaken the overall magnetism. Alnico, for example, uses nickel in the alloy and makes a good permanent magnet. Added to some kinds of stainless steel, nickel makes the material non-magnetic.
Some elements in the group called rare earths exhibit very strong magnetic properties. Neodymium, in particular, when alloyed with iron and boron makes the strongest permanent magnets so far discovered. Tiny neodymium magnets have made small, powerful electric motors possible, as well as the ear buds you use with your MP3 player. The rare earth samarium, alloyed with cobalt, also makes strong magnets. Samarium, though somewhat weaker than neodymium, retains its magnetism better at high temperatures.
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