Previously unknown cubic ordered Ni7Al and Cu7Pt compounds have recently been theoretically predicted to be stable phases in the Ni-Al and Cu-Pt systems. While Cu7Pt was subsequently synthesized and identified, Ni7Al remains experimentally unobserved. Using first-principles total energy calculations, we reinvestigate the stability of this Ni7Al compound. We find the stability of this compound to be qualitatively effected by spin polarization, ignored in previous calculations. The effect of ferromagnetism is to stabilize the two-phase mixture of Ni+Ni3Al relative to the Ni7Al compound such that the latter is stable in nonmagnetic calculations, but unstable when spin polarization is taken into account. This reversal of relative stabilities of Ni7Al and Ni+Ni3Al with magnetism also has a dramatic effect on the calculated Ni3Al/Ni interfacial energy s and spin-polarized calculations lead to a positive value of s, which is in qualitative agreement with values obtained from precipitation experiments.
|Original language||English (US)|
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 1999|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics