  We have studied the magnetic and transport properties of an
ultra-low-resistivity two-dimensional electron system in a Si/SiGe quantum
well. The spin polarization increases linearly with the in-plane magnetic field
and the enhancement of the spin susceptibility is consistent with that in
Si-MOS structures. Temperature dependence of resistivity remains metallic even
in strong magnetic fields where the spin degree of freedom is frozen out. We
also found a magnetoresistance anisotropy with respect to an angle between the
current and the in-plane magnetic field.
