Activation energies for spin-reversed excitations in the fractional   quantum Hall effect
  The activation energy measured in transport experiments in the fractional Hall regime corresponds to the energy required to create a far separated particle hole pair. We calculate, for several fractional quantum Hall states, the energy gaps for the excitation in which the excited composite fermion reverses its spin quantum number. Our results indicate that such spin reversed excitations may be relevant in experimentally accessible regimes. 
Sudhansu S. Mandal and J.K. Jain