Development of thermoelectric Bi-based cobaltites with an easy axis of magnetization parallel to the c-axis for magnetic alignment

Toshiaki Kumagai, Shigeru Horii, Tetsuo Uchikoshi, Tohru Suzuki, Yoshio Sakka, Taichi Okamoto, Jun Ichi Shimoyama, Kohji Kishio

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Abstract

We report the conversion of the easy axis of magnetization from the c-axis to the c-axis in thermoelectric misfit-layered Bismuth-based cobaltites for a magnetic grain-alignment process. The conversion was accomplished by the substitution of Ca for Sr in the block layer of [(B 0.5 Pb 0.5 ) 2 Sr 2 O 4 ] 2 Sr 2 O 4 ] 0.55 .CoO 2 Moreover, magnetic anisotropy along the c-axis was enhanced by partial substitution of Pr for Ca in [(Bi 0.5 Pb 0.5 ) 2 Ca 2 O 4 ] z CoO 2 . From the analysis of their crystal structures, we concluded that the doping of Pr and Ca played a role in distortion of the block layer, indirectly leading to changes in the local structure of the CoO 2 layers and magnetic anisotropy. The c-axis grain-aligned bulk has been successfully fabricated by a magnetic grain-alignment method in 10 T, and a drastic reduction in the resistivity perpendicular to the applied field and the grain-oriented microstructure were observed. magnetic alignment, easy axis of magnetization, thermoelectric materials, [Bi 2 Sr 2 O 4 ] 0.55 CoO 2 , misfit crystal structure

Original languageEnglish
JournalJapanese Journal of Applied Physics, Part 2: Letters
Volume44
Issue number37-41
DOIs
Publication statusPublished - 2005 Sep 30
Externally publishedYes

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ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy (miscellaneous)
  • Physics and Astronomy(all)

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