  Using the full-potential local orbital minimum-basis method,the Ti2-based
full-Heusler alloys are studied. The results show that these compounds exhibit
a half-metallic behavior, however, in contrast to the conventional full-Heusler
alloys,the full-Heusler alloys show a Slater-Pauling behavior and the total
spin magnetic moment per unit cell(Mt) following the rule Mt=Zt-18. The origin
of the gap in these half-metallic alloys are well understood. It is found that
the half-metallic properties of Ti2-based compounds are insensitive to the
lattice distortion and a fully spin polarization can be obtained within a wide
range of lattice parameters. This is favorable in practical application.
