# Stern Gerlach Gradient Field Strength

## Main Question or Discussion Point

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.

~Robert

Related Quantum Physics News on Phys.org
Hans de Vries
Gold Member
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.

$$\vec{F}_{magn}\ =\ \textsf{grad}\left( \vec{\mu}_e\cdot \textsf{B} \right)$$

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

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

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: