  We study the appearance of induced parity-violating magnetic moment, in the
presence of external magnetic fields, for even-number of fermion species
coupled to dynamical fields in three dimensions. Specifically, we use a
SU(2)xU(1) gauge model for dynamical gauge symmetry breaking, which is also
proposed recently as a field theoretical model for high-temperature
superconductors. By decomposing the fermionic degrees of freedom in terms of
Landau levels, we show that, in the effective theory with the lowest Landau
levels, a parity-violating magnetic moment interaction is induced by the higher
Landau levels when the fermions are massive. The possible relevance of this
result for a recently observed phenomenon in high-temperature superconductors
is also discussed.
