  We investigate the ground state competition at the transition from the spin
unpolarized to spin ordered phase at filling factor $\nu=2/3$ in single layer
heterostructure and at $\nu=2$ in double layer quantum well. To trace the
quantum Hall phase we use the minimum in the dissipative conductivity
$\sigma_{xx}$. We observe two different transition scenarios in two
investigated situations. For one of them we propose a qualitative explanation,
based on the domain structure evolution in the vicinity of the transition
point. The origin for the second scenario, corresponding to the experimental
situation at $\nu=2$ in double layer 2DES, still remains unclear.
