Magnets Part 2 -
Inside a Magnet
There are 2 types of magnets:
1. Temporary Magnets
can be magnetized for a short period
of time by rubbing the item in one direction with the pole of a strong magnet.
2. Permanent Magnets
This is hard to magnetize but stays magnetic for a long time.
a Material that shows strong magnetic properties is said to be a FERROMAGNETIC material!
But... some atoms contain electrons that are not paired!
These atoms tend to HAVE STRONG MAGNETIC PROPERTIES!
The pre-fix "ferro" comes from the
latin word "Ferrum" meaning Iron!
Why are some materials magnetic while others are not?
common materials such as Nickel, Cobalt, and
Gadolinium are ferromagnetic, as are the more rare
samarium and neodymium which make very strong
magnets!
The magnetic properties of a material depend on the structure of its atoms!
Each electron in an atom has a property called the electron spin in which the spinning electron
produces a magnetic field that makes the electron behave like a tiny magnet
Magnetic Domains
In certain materials the magnetic fields of many atoms are aligned with one another. A grouping of atoms that have their magnetic fields aligned are known as a magnetic domain. This domain then acts like a bar magnet with a North and South pole.
But if the domains are pointing in random directions
then they will not be magnetized because they cancel each other out. So this material is NOT a magnet
When domains are going in the same or mostly the same
direction, they are magnetized
In most atoms electrons form pairs that spin in opposite directions which produce opposite magnetic fields canceling each other out. So these atoms have WEAK magnetic properties