  We study the spin-ordering and the magnon collective modes of the
two-dimensional Wigner crystal state at strong magnetic fields. Our work is
based on the Hartree-Fock approximation for the ground state and the
time-dependent Hartree-Fock approximation for the collective modes. We find
that the ground state is ferromagnetic, i.e that all spins are aligned at T=0
even when the electronic g-factor is negligibly small. The magnon calculations
show that the spin-stiffness is much smaller in the crystal state than in fluid
states which occur at nearby Landau level filling factors.

Condensed Matter