The skin effect in normal metals is a direct consequence of Faraday's Law of Induction. This describes how a time varying magnetic flux generates a circulating electric field. A simple picture to have in your mind is a loop of wire rotating about an axis perpendicular to a magnetic field. In this way, the magnetic flux through the loop changes in time. Whenever this happens, an electric current flows in the loop such that the field induced by that current opposes the change in the magnetic flux. This is how we generate the vast majority of our electric power in the United States. There is really no difference in the manner in which electricity is generated when one compares coal, nuclear, hydroelectric, or wind power plants. All that is different is the source of the energy used to rotate the coil.

So, what does that have to do with a metallic sample in our measurement apparatus? Well, it turns out that the physics does not care how the change in magnetic flux is created. All that matters is that there is a change. One can rotate a coil of wire in a static magnetic field, or one can rotate a magnetic field about a static coil. And again, one can just change the strength of the magnetic field without any rotation involved at all. The net result is an electric current such that the current's associated magnetic field opposes the change in magnetic flux.

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My Interpretations of Some Things
Local Moment vs. Itinerant Systems
Types of Magnetic Order
How a TDR Works
The Normal Skin Effect

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Matt's Home

If you have any questions, feel free to email me at vannette@iastate.edu



Updated 22 April 2007 from the lab.