The site preference of 3d atoms Y in Mn2YAl (Y = V, Fe, Co) alloys and its influence on their electronic structures and magnetism have been studied by first-principles calculations. The results prove that elements with more valence electrons than Mn tend to enter the A (0, 0, 0) and C (, , ) sites and elements with fewer electrons prefer the B (, , ) site (Wyckoff positions). Meanwhile, it is found that for Mn2VAl and Mn2FeAl, a high spin polarization can be obtained whether the Y atom enters the (A, C) or the B site. In particular, Mn2VAl is half-metallic whether it forms the Cu2MnAl type or the Hg2CuTi type of structure. And a 100% spin polarization can be retained even when a 25% Mn-V antisite disorder occurs. This is quite preferable in practical applications. It is also found that the higher-valent element such as Co at the B (, , ) site has opposite effects and tends to close the energy gap. Finally, a systemic summarization on the electronic and magnetic properties of Mn2YAl (Y = Ti, V, Cr, Mn, Fe and Co) alloys was made. All of them except for Mn2TiAl are predicted as half-metals. The calculated total spin moment is an integral value and increases from -3νB/f.u. for Mn2TiAl to +2νB/f.u. for Mn2CoAl with increasing number of valence electrons. This agrees with the Slater-Pauling curve quite well. All the Mn2YAl alloys studied here are ferrimagnets.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Acoustics and Ultrasonics
- Surfaces, Coatings and Films