Some of you may know that the full content of so-called Feynman lectures have been available on-line for some time now, at the Caltech Institute of Technology. This includes the lecture on magnetic materials.
- All Feyman lectures
- Chapter 37: magnetic materials
- A forum is associated with the lecture, where on can raise questions. Could you address this one?
It is known that the magnetic field in a permanent magnet is caused by the spinning motions of certain electrons. In a bar magnet for example, the axes of rotation of these electrons are parallel (mostly) to the long axis of the bar magnet. If one were to put the bar magnet into a high speed motor and spin it parallel to its long axis, would the magnetic field from the magnet decrease (or increase with the opposite direction)? If one could spin the magnet fast enough, could they turn off the “permanent" magnet?