Relaxation times in cyclotron resonance in metals

The relation between an effective relaxation time τ in cyclotron resonance, mass anisotropy and magnetic field tipping is studied and a true relaxation time τ₀ is extracted by comparison with measurements. It is found that for copper τ has a maximum value in a slightly tipped magnetic field and that in potassium τ decreases monotonically with increasing tip angle. This is explained in terms of the Fermi surfaces of these metals.