What is a Permanent Magnet?
Most material is non-magnetic. It is composed of molecules made of atoms, each of which have electrons orbiting nuclear protons, but where the motion of one electron, essentially a tiny electric current, generates a magnetic field that is cancelled by the magnetic field generated by the motion of another electron. In magnetic materials this cancellation is incomplete, and so the atoms of the material have small net electric currents and they thus generate small magnetic fields. For various reasons having to do with the intricacies of atomic physics, this tends to happen for certain substances, like cobalt, nickel, and, of course, iron. Within these magnetic materials, the magnetic fields of the various atoms exert torques on the electric currents of their neighboring atoms, causing the atoms to align and their magnetic fields to add together constructively. As a result, the material exhibits a magnetic field. It is a magnet. Most magnets are like the bar magnet shown in the illustratio
Most material is non-magnetic. It is composed of molecules made of atoms, each of which have electrons orbiting nuclear protons, but where the motion of one electron, essentially a tiny electric current, generates a magnetic field that is cancelled by the magnetic field generated by the motion of another electron. In magnetic materials this cancellation is incomplete, and so the atoms of the material have small net electric currents and they thus generate small magnetic fields. For various reasons having to do with the intricacies of atomic physics, this tends to happen for certain substances, like cobalt, nickel, and, of course, iron. Within these magnetic materials, the magnetic fields of the various atoms exert torques on the electric currents of their neighboring atoms, causing the atoms to align and their magnetic fields to add together constructively. As a result, the material exhibits a magnetic field. It is a ‘magnet’. Most magnets are like the bar magnet shown in the illustrat
A permanent magnet is a magnet that is permanent, in contrast to an electromagnet, which only behaves like a magnet when an electric current is flowing through it. Permanent magnets are made out of substances like magnetite (Fe3O4), the most magnetic naturally occurring mineral, or neodymium, a powerfully magnetic synthetic substance. The Earth itself is a huge permanent magnet, though its magnetic field is quite weak relative to its size. Humans have used the magnetic field of the Earth for navigation since the compass was invented in ancient China. Even the most powerful permanent magnet is not as strong as the stronger electromagnets, so their applications are limited, but they still have many uses. The most mundane would be use as refrigerator magnets, but magnets can be found everywhere, including your hard disk, ATM and credit cards, speakers and microphones, electric motors, and toys. Electric motors work through an interaction between an electromagnet and a permanent magnet. Ev
