Distinct impact of order degree on thermoelectric power factor of p-type full-Heusler Mn2VAl compounds

Hezhang Li, Kei Hayashi, Jinfeng Dong, Jing Feng Li, Yuzuru Miyazaki

Research output: Contribution to journalArticle

Abstract

Full-Heusler compounds have three crystal structures with a different order degree; the highly ordered L21, partially disordered B2, and completely disordered A2 structures. To reveal the effects of the order degree on thermoelectric (TE) properties of the full-Heusler compounds, Mn2VAl samples with varied L21 and B2 order degrees are prepared by changing preparation conditions, and their Seebeck coefficients and electrical conductivities are measured in a wide temperature range. As the B2 order degree becomes higher, the Seebeck coefficient increases, leading to the increase of the power factor (PF). The maximum PF is 2.84 10-4 Wm-1 K-2 at 767 K for the Mn2VAl sample with the highest B2 order degree. This study demonstrates that the TE properties of Mn2VAl can be enhanced by increasing the fraction of the B2 phase. A relation between the Seebeck coefficient and crystal structures is also discussed based on the calculation of the electronic density of states of Mn2VAl with the L21 and B2 structures.

Original languageEnglish
Article number055503
JournalMaterials Research Express
Volume7
Issue number5
DOIs
Publication statusPublished - 2020 May

Keywords

  • electronic density of states
  • full-Heusler
  • Mn2VAl
  • order degree
  • thermoelectric properties

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Metals and Alloys

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