Temperature dependence of the spin polarization of a quantum Hall ferromagnet

The absolute spin polarization of a two-dimensional electron gas has been measured as a function of temperature at the ν=1 quantum Hall state by magnetoabsorption spectroscopy. We find that the electrons become fully polarized as T→0 and that the loss of spin polarization over the temperature regime of 500 mK to 12 K is consistent with a recently proposed continuum quantum ferromagnet model of the spin thermodynamics of the ν=1 quantum Hall effect state.