Abstract: The electronic band structures of three ordered states of half-Heusler NiMnSb were calculated by means of LAPW method according to first-principle. The result indicates that the transition disorder between different ordered band states will result in the decreasing of electronic spin polariza bility and disappearing of half-metal character of materials.

Key words: half-metallic, ferromagnetic alloy, half-Heusler stru cture, NiMnSb