Structural, magnetic, transport, and thermoelectric properties of the pseudobrookite AlTi2 O5-Ti3 O5 system

Ryusei Takahama, Toi Ishii, Daigo Indo, Mitsutoshi Arizono, Chieko Terakura, Yoshinori Tokura, Nao Takeshita, Masaaki Noda, Hideki Kuwahara, Takuo Saiki, Takuro Katsufuji, Ryoichi Kajimoto, Tetsuji Okuda

Research output: Contribution to journalArticlepeer-review

Abstract

We investigated the structural, magnetic, transport, and high-temperature thermoelectric properties of single crystals of the pseudobrookite Al1-xTi2+xO5 for 0≤x≤1 grown using a floating zone. We found a correlation of spin-singlet Ti3+-Ti3+ dimers coupled with the lattice even in the conductive α and λ phases which develops with increasing x. This developing dimer correlation reduces the number of unpaired Ti3+ ions, which makes the compound more conductive owing to the suppression of disorder for x up to about 0.75. The dimer fluctuation causes a critical enhancement of the magnetic susceptibility at around 150 K in the λ phase near the boundary (x∼0.9) between the λ and the β phases. Such a correlation of the spin-singlet Ti3+-Ti3+ dimers may produce a high Seebeck coefficient in the conductive α and λ phases leading to a large thermoelectric power factor at high temperatures.

Original languageEnglish
Article number074401
JournalPhysical Review Materials
Volume4
Issue number7
DOIs
Publication statusPublished - 2020 Jul

ASJC Scopus subject areas

  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)

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