Doping effects on thermoelectric properties of the off-stoichiometric Heusler compounds Fe{sub 2−x}V{sub 1+x}Al

Journal Article · Fri Mar 28 04:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4869395· OSTI ID:22271135

Tamada, Y. ^[1]

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1. Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

The thermoelectric properties of Heusler-type Fe{sub 2−x}V{sub 1+x}Al{sub 1−y}Si{sub y} and Fe{sub 2−x}V{sub 1+x−y}Ti{sub y}Al alloys have been investigated to clarify which off-stoichiometric alloy, i.e., V-rich (x > 0) or V-poor (x < 0), is more effective in enhancing the Seebeck coefficient when doped by Si and Ti, while retaining a low electrical resistivity. Large Seebeck coefficients of −182 μV/K and 110 μV/K at 300 K are obtained for n-type Fe{sub 1.95}V{sub 1.05}Al{sub 0.97}Si{sub 0.03} and p-type Fe{sub 2.04}V{sub 0.93}Ti{sub 0.03}Al, respectively. When the Seebeck coefficient is plotted as a function of valence electron concentration (VEC), the VEC dependence for the doped off-stoichiometric alloys falls on characteristic curves depending on the off-stoichiometric composition x. It is concluded that a larger Seebeck coefficient with a negative sign can be obtained for the V-rich alloys rather than the V-poor alloys, whilst good p-type materials are always derived from the V-poor alloys. Substantial enhancements in the Seebeck coefficient for the off-stoichiometric alloys could be achieved by a favorable modification in the electronic structure around the Fermi level through the antisite V or Fe defect formation.

• OSTI ID: 22271135
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 12 Vol. 115; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CONCENTRATION RATIO
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
ELECTRONIC STRUCTURE
ELECTRONS
FERMI LEVEL
HEUSLER ALLOYS
SEEBECK EFFECT
THERMOELECTRIC PROPERTIES
VALENCE
VANADIUM ALLOYS