Magnetic field dependence of Pauli spin blockade: a window into the   sources of spin relaxation in silicon quantum dots
  We investigate spin relaxation in a silicon double quantum dot via leakage current through Pauli blockade as a function of interdot detuning and magnetic field. A dip in leakage current as a function of magnetic field on a \sim 40 mT field scale is attributed to spin-orbit mediated spin relaxation. On a larger (\sim 400 mT) field scale, a peak in leakage current is seen in some, but not all, Pauli-blocked transitions, and is attributed to spin-flip cotunneling. Both dip and peak structure show good agreement between theory and experiment. 
G. Yamahata, T. Kodera, H. O. H. Churchill, K. Uchida, C. M. Marcus,   S. Oda
cond-mat.mes-hall quant-ph