Imagine an electron in orbit around the nucleus being subjected to a strong magnetic field,
The electron's orbit is squeezed until both sets of magnetic field lines, those from the applied magnetic field and those due to the electron in orbit, align. The temperature gradient is similarly squeeze and heat is loss. When the magnetic field is removed, the electron orbit returns to its original size, \(r_{e2}\), the heat under the lower (squeezed) temperature curve redistributes and the new temperature gradient has a lower starting temperature.
Magnetic cooling in action!
This qualitative description will bring us closer to quantifying the process. Immediately, this description suggest a magnetic field strength greater than a minimum threshold before magnetic cooling can occur. This minimum is of course the magnetic moment of the electron in orbit. It also suggest a specific orientation, where both magnetic fields are in parallel for maximum efficiency. It is possible to set the system into resonance for rapid cooling. And, if the applied field is reversed, the orbit might expand and results in the material heating up. (An expanding/contracting orbit would suggest that a third constrain, magnetic moment, other than centripetal force and electrostatic attraction, also determines orbital radius, \(r_e\).)
Until next time.
