What is the difference between ferromagnetic, paramagnetic and diamagnetic substances?
In: Physics
Magnetism is caused by the “direction” or “spin” of electrons that are not bound to each other called “unpaired electrons”
When an object can change the “spin” of its “unpaired electrons” permanently they are called ferromagnetic (Ferro is a word for Iron which is the most famous magnetic metal.)
When an object can temporarily change the spin of its unpaired electrons (and usually does a poor job of it) then it is called Paramagnetic.
Both of the above types (ferro and para) change their electrons to match the direction of a magnetic field.
Substances that are diamagnetic change their spins to be the opposite direction of a magnetic field. Most things that are not Ferro- or para-magnetic are diamagnetic; however most of them are really bad at it so the effects are hard to notice. For instance water is diamagnetic.
(I don’t do a lot of ELI5, so I hope I got the point across)
Say you have a strong electromagnet that you can switch on and off and you put these three types of materials near it. All three will become magnetized, meaning each will start producing their own magnetic field. The paramagnetic and ferromagnetic material will produce a field that is aligned with the external magnetic field, and the diamagnetic will produce a (typically very weak) feild that is in the opposite direction. Now turn the electromagnet off. The ferromagnetic material will continue to be magnetized, while the paramagnetic and diamagnetic material will revert back to being non-magnetic and their self produced field will collapse as soon as the magnet is turned off.
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