Structural stability and magnetism of metastable Ni-Pt intermetallic compounds studied by ab initio calculation

The self-consistent electronic structure calculations were carried out with the accurate frozen-core full-potential projector augmented-wave method on 13 Ni-Pt intermetallic compounds of simple crystalline structures, i.e. A15, D0₁₉, D0₃ and L1₂ Ni₃Pt and NiPt₃, and α-NiAs, B1, B2, L2 _a , and L1₀ NiPt. The calculations reveal that the L1₂ Ni₃Pt, L1₀ NiPt and L1₂ NiPt₃ are energetically more stable than their respective competitive structures, indicating that the three structures may be formed in some appropriate conditions. The obtained results match well with the experimental observation or other theory predictions. It is found that there is hybridization between Ni 3d and Pt 5d states, which may significantly affect the structural stability and magnetism of metastable Ni-Pt intermetallic compounds. Supported by the National Natural Science Foundation of China (Grant Nos. 50531040, 50871058), the Ministry of Science and Technology of China (Grant No. 2006CB605201), and the Administration of Tsinghua University