TY - JOUR
T1 - Structural, magnetic, transport, and thermoelectric properties of the pseudobrookite AlTi2 O5-Ti3 O5 system
AU - Takahama, Ryusei
AU - Ishii, Toi
AU - Indo, Daigo
AU - Arizono, Mitsutoshi
AU - Terakura, Chieko
AU - Tokura, Yoshinori
AU - Takeshita, Nao
AU - Noda, Masaaki
AU - Kuwahara, Hideki
AU - Saiki, Takuo
AU - Katsufuji, Takuro
AU - Kajimoto, Ryoichi
AU - Okuda, Tetsuji
N1 - Funding Information:
We thank Prof. D. I. Khomskiĭ for helpful discussions. This work was supported by the Japan Society for the Promotion of Science (KAKENHI Grant No. 18K03543) and was partly carried out at the Joint Research Center for Environmentally Conscious Technologies in Materials Science (Grant No. JPMXP0618217637) at ZAIKEN, Waseda University.
PY - 2020/7
Y1 - 2020/7
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevMaterials.4.074401
DO - 10.1103/PhysRevMaterials.4.074401
M3 - Article
AN - SCOPUS:85092917185
VL - 4
JO - Physical Review Materials
JF - Physical Review Materials
SN - 2475-9953
IS - 7
M1 - 074401
ER -