SPIN TRANSPORT AND LOCALIZATION IN A MAGNETIC 2-DIMENSIONAL ELECTRON-GAS

Magnetotransport is investigated in a new class of heterostructures wh erein a two-dimensional electron gas (2DEG) is exchange coupled to a 2 D distribution of local moments. Quantum transport in these ''magnetic '' 2DEGs is strongly influenced by the s-d exchange-enhanced spin spli tting, resulting in a highly spin polarized gas beginning at large Lan dau level filling factors. Diffusive transport in low magnetic fields is dominated by modifications of the Hartree corrections to the conduc tivity arising from the giant spin splitting. An anomalous negative ma gnetoresistance at higher magnetic fields suggests the suppression of spin-disorder scattering.