Effect of magnetic field on macrosegregation in (Bi, Sb)2Te3

Hideyuki Yasuda, Itsuo Ohnaka, Yoji Furukubo, Tsuguo Fukuda, Kazuo Watanabe, Han Jun Koh

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

A thermoelectric material (Bi0.25Sb0.75)2Te3 was grown by a vertical gradient freezing technique in high magnetic fields of up to 8 T. The radial distribution of composition showed macrosegregation when the specimens were solidified in the magnetic field. The radial segregation increased with increasing intensity of the magnetic field. On the other hand, the longitudinal distribution for both the specimens under 0 T and 8 T had a variation at the initial transient, but no effect of the magnetic field on the composition distribution was observed. A numerical calculation of the solid/liquid interface shape, thermal and solutal fields suggested that the difference in thermal conductivity between the solid and the liquid phases would cause the concave interface shape and a driving force of the convection around the s/l interface. It was concluded that the interaction of the convection mass transfer reduced by the magnetic field interacts with the diffusion mass transfer, causing the radial macrosegregation.

Original languageEnglish
Pages (from-to)1288-1295
Number of pages8
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume61
Issue number12
DOIs
Publication statusPublished - 1997

Keywords

  • Bridgman method
  • Macrosegregation
  • Magnetic field
  • Thermoelectric materials
  • Unidirectional solidification

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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