Sinusoidal and helical spin density wave states in transition metals

The difference between sinusoidal and helical spin density wave states is discussed in reference to these states of chromium and fee iron. The relative stability between these states against the magnitude of local magnetic moments is investigated. It is shown that for chromium the stable spin density wave state changes from a sinusoidal one to a helical one as the magnitude of local magnetic moments becomes large while for fee iron the stable spin density wave state is always a helical one. The effect of charge modulation associated with sinusoidal spin density wave on the stability is further investigated. It is shown that the charge modulation stabilizes the sinusoidal spin density wave state. The difference in electronic structure between sinusoidal and helical spin density wave states is also elucidated.