Permanent Magnets: Electron Spin & Magnetic Fields

In summary, the special condition with a permanent magnet is that all the electrons are circling uniformly in the same direction, causing a magnetic field. Each orbiting electron can be considered as a current loop, and if there is a predominant orientation of these loops, the object is considered a magnet.
  • #1
Rockazella
96
0
My physics teacher gave the class a brief explanation of a permanent magnet. If I understood him correctly he basically said the special condition with a permanent magnet is that all the electrons are circling uniformly (in same direction). The poles of the magnet are based on the direction the electrons are spinning (right hand rule).

My question is why would those uniform circling electrons cause a magnetic field?
 
Physics news on Phys.org
  • #2
They actually don't circle all uniformly, but never mind the difference.

Basicly each orbiting electron can be considered as a current loop (it is quantum loop, but that is unimportant here). If loops are randomly oriented, then macroscopic magnetic field (average over many atoms) is zero, but if there is predominant orientation then average field is not zero any more, and we call an object with such orientations "a magnet".
 
  • #3


The reason for this is due to the fact that electrons have a property called spin, which is a form of angular momentum. When these electrons are circling in the same direction, their spins are aligned, creating a net magnetic moment. This net magnetic moment then produces a magnetic field around the magnet.

Furthermore, the direction of the magnetic field is determined by the direction of the electron spins. This is where the right hand rule comes into play. When using the right hand rule, the direction of the magnetic field is determined by the direction in which the electrons are spinning.

In addition, the strength of the magnetic field is determined by the number of electrons and the strength of their spin. The more electrons that are aligned and spinning in the same direction, the stronger the magnetic field will be.

It's important to note that not all materials can become permanent magnets. Only certain materials, such as iron, nickel, and cobalt, have the ability to align their electrons and create a permanent magnetic field. This is due to their atomic structure and the ability of their electrons to easily align and maintain their spin.

Overall, the uniform circling of electrons in a permanent magnet creates a magnetic field due to their aligned spins, which then produces the attractive and repulsive forces we associate with magnets.
 

1. What is a permanent magnet?

A permanent magnet is a material that produces a magnetic field without the need for an external electric current. It is made up of atoms with aligned electron spins, which creates a net magnetic field.

2. How do permanent magnets work?

Permanent magnets work by aligning the electron spins of the atoms within the material in the same direction. This produces a magnetic field that can attract or repel other magnets or magnetic materials.

3. How are permanent magnets made?

Permanent magnets are typically made by exposing certain materials, such as iron or cobalt, to a strong magnetic field. This aligns the electron spins in the same direction, creating a permanent magnetic field. The material is then cooled to "freeze" the alignment of the electron spins.

4. Can permanent magnets lose their magnetism?

Yes, permanent magnets can lose their magnetism over time, especially if they are exposed to high temperatures. This can cause the electron spins to become disordered and cancel out the magnetic field. Additionally, strong external magnetic fields can also demagnetize permanent magnets.

5. What are the applications of permanent magnets?

Permanent magnets have a wide range of applications, including in electric motors, generators, speakers, hard drives, and magnetic separation. They are also used in MRI machines, as well as in many everyday items such as refrigerator magnets and magnetic toys.

Similar threads

  • Electromagnetism
Replies
2
Views
801
  • Electromagnetism
Replies
5
Views
940
Replies
6
Views
835
Replies
8
Views
2K
Replies
1
Views
1K
Replies
24
Views
2K
  • Electromagnetism
3
Replies
74
Views
12K
  • Electromagnetism
Replies
17
Views
1K
Replies
2
Views
503
Replies
14
Views
808
Back
Top