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Title: Enhanced power factor of higher manganese silicide via melt spin synthesis method

We report on the thermoelectric properties of the higher manganese silicide MnSi{sub 1.75} synthesized by means of a one-step non-equilibrium method. The ultrahigh cooling rate generated from the melt-spin technique is found to be effective in reducing second phases, which are inevitable during the traditional solid state diffusion processes. Aside from being detrimental to thermoelectric properties, second phases skew the revealing of the intrinsic properties of this class of materials, for example, the optimal level of carrier concentration. With this melt-spin sample, we are able to formulate a simple model based on a single parabolic band that can well describe the carrier concentration dependence of the Seebeck coefficient and power factor of the data reported in the literature. An optimal carrier concentration around 5 × 10{sup 20 }cm{sup −3} at 300 K is predicted according to this model. The phase-pure melt-spin sample shows the largest power factor at high temperature, resulting in the highest zT value among the three samples in this paper.
Authors:
;  [1] ; ;  [2] ;  [3] ; ;  [2]
  1. Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  2. State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)
  3. (China)
Publication Date:
OSTI Identifier:
22399185
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CHARGE CARRIERS; CONCENTRATION RATIO; COOLING; DIFFUSION; MANGANESE SILICIDES; POWER FACTOR; SEEBECK EFFECT; SOLIDS; SPIN; SYNTHESIS; TEMPERATURE DEPENDENCE; THERMOELECTRIC PROPERTIES