Magnetic and Electrical Properties of Nonequilibrium NiAl Alloys Produced by Vapor Quenching

Abstract

In sputter‐deposited Ni1−xAlx alloys, a disordered f. c. c. phase appears for 0 ≦ x < 0.3 and 0.85 < x ≦ 1.0, the B2 type ordered phase for 0.35 < x < 0.6, a disordered b. c. c. phase for 0.6 < x < 0.65, and an amorphous phase for x = 0 to 0.15 are ferromagnetic, while the other phases are paramagnetic down to 4.2 K. The electrical resistivity at 4.2 K, ϱ(4.2), is small and the temperature coefficient of electrical resistivity, TCR, is positive for the disordered f. c. c. and ordered b. c. c. alloys, while ϱ(4.2) is very large and TCR is negative for the disordered b. c. c. and amorphous alloys.

Free energy and vibrational entropy difference between ordered and disorderedNi3Al

“…42 We also note that fcc disordered Ni 3 Al is ferromagnetic, whereas L1 2 ordered Ni 3 Al is not. 40,43 In order to gain more information on the nature of the vibrational difference, we also evaluated the root-meansquared ͑rms͒ displacement of the Ni and Al atoms in both ordered and disordered samples. We find that the largest difference comes from the Al atoms, which exhibit a larger amplitude in the disordered phase than in the ordered phase at all temperatures, but especially at low temperatures, where the Al atoms vibrate with an amplitude 20-10 % higher than in the ordered phase between 100 and 200 K, respectively.…”

Oxidation of RuAl and NiAl Thin Films: Evolution of Surface Morphology and Electrical Resistance

“…Additionally, the film stresses are easily controlled in cosputtered films by adjusting the sputtering pressure. NiAl films (thin film: 24-54 μΩ · cm) [23], [26]- [28] and bulk RuAl (bulk: 13-65 μΩ · cm) [29], [30] are more conductive and more oxidation resistant than Si (bulk resistivity: 1-100 mΩ · cm) [31], [32] and SiGe (resistivity: 0.5-75 mΩ · cm) [33], [34]. NiAl and RuAl are also resistant to various forms of chemical attack, making them useful in severe environments.…”