Low-Spin <math>γ -Fe-Ni (γLS)</math> in <math>Fe-Ni</math> Bearing Meteorites: Epitaxial Intergrowth of <math>γLS</math> and Tetrataenite as Possible Equilibrium State at <math> 20-40</math> at <math>% Ni</math>

Physics NotePublished

Low-Spin $<math>\gamma -Fe-Ni (\gamma_{LS})</math>$ in $<math>Fe-Ni</math>$ Bearing Meteorites: Epitaxial Intergrowth of $<math>\gamma_{LS}</math>$ and Tetrataenite as Possible Equilibrium State at $<math>\sim 20-40</math>$ at $<math>% Ni</math>$

D. G. Rancourt; R. B. Scorzelli

1995

Authors: D. G. Rancourt; R. B. Scorzelli
Type: Physics Note
Status: Published
Publication date: 1995
Description: We argue that the so called paramagnetic phase seen by Mössbauer spectroscopy in taenite lamella from octahedrites meteorites, ataxites meteorites, the metal particles of Fe-Ni-bearing chondrites meteorites, and synthetic particle irradiated Fe-Ni alloys is a low-spin <math>\gamma -Fe-Ni\!\,</math> phase <math>(\gamma_{LS})\!\,</math> related to the close packed low-spin phases seen in the pressure-temperature phase diagrams of both metallic Fe and synthetic Fe-Ni alloys and many other Fe-alloy systems. At a given composition, this <math>\gamma_{LS}\!\,</math> phase is quite distinct from the ordinary (high-spin) <math>\gamma\!\,</math>-phase <math>(\gamma_{HS})\!\,</math> in that it has a different electronic structure associated with very different magnetic properties (small-moment antiferromagnetism versus large-moment ferromagnetism) and a lower lattice parameter. It should be considered a new mineral for which we suggest the name antitaenite. We further propose that in the meteorites <math>\gamma_{LS}\!\,</math> always occurs in a fine epitaxial intergrowth with tetrataenite (atomically ordered FeNi). This resolves outstanding difficulties in meteoritic and particle irradiated Fe-Ni metallurgy.
Year: 1995
Number: CBPF-NF-011/95
Linked to a thesis: No
Linked to a grant: No