Elastic and dynamical structural properties of la and Mn-doped SrTiO3 studied by neutron scattering and their relation with thermal conductivities

Ryoichi Kajimoto, Mitsutaka Nakamura, Naoki Murai, Shin Ichi Shamoto, Takashi Honda, Kazutaka Ikeda, Toshiya Otomo, Hiroto Hata, Takahiro Eto, Masaaki Noda, Hideki Kuwahara, Tetsuji Okuda

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The electron-doped SrTiO3 exhibits good thermoelectric properties, which makes this material a promising candidate of an n-type oxide thermoelectric device. Recent studies indicated that only a few percent co-doping of La and Mn in SrTiO3 substantially reduces the thermal conductivity, thereby greatly improving the thermoelectric figure of merit at room temperature. Our time-of-flight neutron scattering studies revealed that by doping both La and Mn into SrTiO3, the inelastic scattering spectrum shows a momentum-independent increase in the low-energy spectral weight approximately below 10 meV. The increase in the low-energy spectral weight exhibits a clear correlation with thermal conductivity. The correlation is attributed to dynamical and local structural fluctuations caused by the Jahn-Teller instability in Mn3+ ions coupled with the incipient ferroelectric nature of SrTiO3, as the origin of the low thermal conductivity.

Original languageEnglish
Article number9651
JournalScientific reports
Volume8
Issue number1
DOIs
Publication statusPublished - 2018 Dec 1

All Science Journal Classification (ASJC) codes

  • General

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