Detail publikace

Antiferrodistortive phase transition in EuTiO3

GOIAN, V. KAMBA, S. PACHEROVÁ, O. DRAHOKOUPIL, J. PALATINUS, L. DUŠEK, M. ROHLÍČEK, J. SAVINOV, M. LAUFEK, F. SCHRANZ, W. FUITH, A. KACHLÍK, M. MACA, K. SHKABKO, A. SAGARNA, L. WEIDENKAFF, A. BELIK, A.

Originální název

Antiferrodistortive phase transition in EuTiO3

Anglický název

Antiferrodistortive phase transition in EuTiO3

Jazyk

en

Originální abstrakt

X-ray diffraction, dynamical mechanical analysis, and infrared reflectivity studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics. Near 300 K, the perovskite structure changes from cubic Pm3m to tetragonal I4/mcm due to antiphase tilting of oxygen octahedra along the c axis. The phase transition is analogous to SrTiO3. However, some ceramics as well as single crystals of EuTiO3 show different infrared reflectivity spectra bringing evidence of a different crystal structure. In such samples, electron diffraction revealed an incommensurate tetragonal structure with modulation wave vector q =0.38 a. Extra phonons in samples with modulated structure are activated in the IR spectra due to folding of the Brillouin zone. We propose that defects such as Eu3+ and oxygen vacancies strongly influence the temperature of the phase transition to antiferrodistortive phase as well as the tendency to incommensurate modulation in EuTiO3.

Anglický abstrakt

X-ray diffraction, dynamical mechanical analysis, and infrared reflectivity studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics. Near 300 K, the perovskite structure changes from cubic Pm3m to tetragonal I4/mcm due to antiphase tilting of oxygen octahedra along the c axis. The phase transition is analogous to SrTiO3. However, some ceramics as well as single crystals of EuTiO3 show different infrared reflectivity spectra bringing evidence of a different crystal structure. In such samples, electron diffraction revealed an incommensurate tetragonal structure with modulation wave vector q =0.38 a. Extra phonons in samples with modulated structure are activated in the IR spectra due to folding of the Brillouin zone. We propose that defects such as Eu3+ and oxygen vacancies strongly influence the temperature of the phase transition to antiferrodistortive phase as well as the tendency to incommensurate modulation in EuTiO3.

Dokumenty

BibTex


@article{BUT93446,
  author="Veronica {Goian} and Stanislav {Kamba} and Oliva {Pacherová} and Jan {Drahokoupil} and Lukáš {Palatinus} and Michal {Dušek} and Jan {Rohlíček} and Maxim {Savinov} and František {Laufek} and Wilfried {Schranz} and Armin {Fuith} and Martin {Kachlík} and Karel {Maca} and Andrey {Shkabko} and Leyre {Sagarna} and Anke {Weidenkaff} and A.A. {Belik}",
  title="Antiferrodistortive phase transition in EuTiO3",
  annote="X-ray diffraction, dynamical mechanical analysis, and infrared reflectivity studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics. Near 300 K, the perovskite structure changes from cubic Pm3m to
tetragonal I4/mcm due to antiphase tilting of oxygen octahedra along the c axis. The phase transition is analogous to SrTiO3. However, some ceramics as well as single crystals of EuTiO3 show different infrared reflectivity spectra bringing evidence of a different crystal structure. In such samples, electron diffraction revealed an incommensurate tetragonal structure with modulation wave vector q =0.38 a. Extra phonons in samples with modulated structure are activated in the IR spectra due to folding of the Brillouin zone. We propose that defects such as Eu3+ and oxygen vacancies strongly influence the temperature of the phase transition to antiferrodistortive phase as well as the tendency to incommensurate modulation in EuTiO3.",
  address="AMER PHYSICAL SOC",
  chapter="93446",
  institution="AMER PHYSICAL SOC",
  number="054112",
  volume="86",
  year="2012",
  month="august",
  pages="054112-1--054112-9",
  publisher="AMER PHYSICAL SOC",
  type="journal article in Web of Science"
}