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Minimum energy for a spin flip?

  1. Apr 29, 2007 #1
    Is there a minimum energy to flip the intrinsic spin of an electron from up to down or vice versa? Or does it depend on the applied B field?
  2. jcsd
  3. Apr 29, 2007 #2
    The external B field is necessary to induce a spin flip (spin down to spin up for example). The associated energy depends on this B field but the also on the spin magnetic moment (or more specifically the z-component thereof). This quantity is expressed in terms of a constant called the Bohr magneton. Lots of imaging techniques (MRI) are based upon the principle of "inducing spin flips" (NMR).

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