The Fe1− xCoxS system ( x < 0.25); transition and the high temperature phase
The α-transition in Fe 1− x Co x S materials is examined based on electrical, magnetic and structural properties. A decrease of the transition temperature is observed with increasing alloying rate up to x co = 0.24, where the transition is completely cancelled. Beyond this critical concentration the...
Gespeichert in:
Veröffentlicht in: | The Journal of physics and chemistry of solids 1987, Vol.48 (9), p.791-802 |
---|---|
Hauptverfasser: | , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | The α-transition in Fe
1−
x
Co
x
S materials is examined based on electrical, magnetic and structural properties. A decrease of the transition temperature is observed with increasing alloying rate up to
x
co = 0.24, where the transition is completely cancelled. Beyond this critical concentration the materials exhibit a high-temperature FeS type behavior.
The existence of
hk0 reflections, with
h and/or
k = 2
n + 1 in the cobalt-stabilized superstructure, the high-temperature phase of FeS, establishes that the structure is hexagonal, space group
P6
3
mc, with two independent metal positions, in contrast to the previously proposed tri-twinned MnP type model.
The physical and structural results are discussed within the framework of conductivity by polarons. The α-transition occurs when the polaron concentration, thermally created or introduced by impurities, reaches the critical value
x
p
≅ 0.08. The driving mechanism for the α-transition is a reduction of the polaron dissociation energy by a temperature increase or by cobalt alloying. |
---|---|
ISSN: | 0022-3697 1879-2553 |
DOI: | 10.1016/0022-3697(87)90029-1 |