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Electron Tunneling Challenge

  1. Dec 19, 2009 #1
    With regards to a Youtube video- Spin polarized tunneling - video #10: , could some one familiar with electronics provide a circuit or diagram for this to work? Also what type & size of barrier could be used?

    This should be fairly easy for any one familiar with electronics, so any help would be appreciated.

    Last edited by a moderator: Sep 25, 2014
  2. jcsd
  3. Dec 19, 2009 #2


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    It is not a "circuit" as such. The main device is a "stack" of different materials, probably a few tens of square microns in size, each layer in the stack will be of the order of a few nanometers thick.
    The actual measurement is then done by measuring the current through the stack as a function of the applied magnetic field.

    Devices like this are made in clean rooms (at universities etc) using a wide variety of (very expensive) equipment for cleaning, deposition, etching etc. It is absolutely impossible to make something like this as home.
  4. Dec 22, 2009 #3
    I have already set up a basic test circuit. I have also collected barriers of different type & size to use. I do not need an expensive science lab to carry out this experiment. I just need to figure out the best way to apply an external magnetic field to achieve the spin polarization change.
  5. Dec 22, 2009 #4


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    How strong the field needs to be depends on the material, in some cases a strong permanent magnet should be enough (the strength needed also depends on the temperature, many of these materials only work when cooled to cryogenic temperatures). There are plenty of webshops that sell strong rare-earth magnets.

    Also, you are somewhat right. You do not need expensive equipment to try the experiment. Expensive equipment is only needed if you want to actually see the effect (which is usually the point of an experiment, but maybe not in this case).
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