In:
Japanese Journal of Applied Physics, IOP Publishing, Vol. 51, No. 8R ( 2012-08-01), p. 085801-
Kurzfassung:
A partially Cr-substituted solid solution of a higher manganese silicide, (Mn 1- x Cr x )Si γ , has been prepared by an arc-melting method and a subsequent annealing process. The compound consists of two tetragonal subsystems of [Mn 1- x Cr x ] and [Si] with an irrational c -axis ratio, γ= c Mn / c Si . According to Vegard's rule, the solubility limit of Cr is determined at x = 0.20. With increasing Cr content x from 0 to 0.20, equivalent to increasing the hole carrier concentration, the a - and c Mn -axis lengths linearly increase, while the c Si -axis length gradually decreases. As expected from a valence electron counting rule, the electrical conductivity of (Mn 1- x Cr x )Si γ increases with increasing x from 334 S·cm -1 ( x = 0) to 727 S·cm -1 ( x = 0.20) at room temperature. The Cr-substituted samples undergo a microscale domain separation; the sample with a nominal composition of x = 0.20 consists of Cr-rich ( x ∼0.3) and Mn-rich ( x ∼0.1) dendritic domains with a typical size of ∼100 µm. Despite the substantial increase in electrical conductivity, the total thermal conductivity decreases with increasing x owing to a marked reduction in lattice contribution. As a consequence, the dimensionless figure-of-merit ZT increases from 0.28 ( x = 0) at 800 K to 0.45 ( x = 0.20) at 900 K.
Materialart:
Online-Ressource
ISSN:
0021-4922
,
1347-4065
DOI:
10.1143/JJAP.51.085801
Sprache:
Unbekannt
Verlag:
IOP Publishing
Publikationsdatum:
2012
ZDB Id:
218223-3
ZDB Id:
797294-5
ZDB Id:
2006801-3
ZDB Id:
797295-7
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