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Stern Gerlach Gradient Field Strength

  1. Jun 10, 2008 #1
    I am trying to recreate the Stern-Gerlach experiment and am having trouble trying to calculate the gradient magnetic field. I am using two magnets with one having a sharp edge and the other flat. I have calculated what the deflection will be of the electron will be in terms of the gradient field, but I do not know how to calculate what the gradient is knowing the dimensions of the magnets.

  2. jcsd
  3. Jun 10, 2008 #2

    Hans de Vries

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    Science Advisor

    Make sure you use the gradient of the inproduct of the magnetic moment and the
    magnetic field rather than the gradient of the magnetic field itself.

    [tex]\vec{F}_{magn}\ =\ \textsf{grad}\left( \vec{\mu}_e\cdot
    \textsf{B} \right)[/tex]

    What you could do is assuming that every little volume of magnetic material is a
    point dipole field like this:

    [tex]\textsf{B}~ = ~ \ \frac{\mu_o\mu_e}{4\pi r^3}\ \ \left(\ 3\ \frac{xz}{r^2}, \quad 3\ \frac{yz}{r^2}, \quad 3\ \frac{zz}{r^2}-1\ \right)[/tex]

    Assuming that they all point in the same direction you can derive the total
    magnetic field by integration (analytic or numerical)

    Regards, Hans.
    Last edited: Jun 10, 2008
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