Indication of the ferromagnetic instability in a dilute two-dimensional   electron system
  The magnetic field B_c, in which the electrons become fully spin-polarized, is found to be proportional to the deviation of the electron density from the zero-field metal-insulator transition in a two-dimensional electron system in silicon. The tendency of B_c to vanish at a finite electron density suggests a ferromagnetic instability in this strongly correlated electron system. 
A. A. Shashkin, S. V. Kravchenko, V. T. Dolgopolov, and T. M. Klapwijk