Antiferrodistortive phase transition in EuTiO3

Abstract

X-ray diffraction, dynamical mechanical analysis and infrared reflectivity studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics. Near 300K the perovskite structure changes from cubic Pm-3m to tetragonal I4/mcm due to antiphase tilting of oxygen octahedra along the c axis (a0a0c- in Glazer notation). 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 wavevector 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 like 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.

PRB, in press

References in corpus (3)

• Magnetodielectric effect and optic soft mode behaviour in quantum paraelectric EuTiO3 ceramics
• First-principles prediction of oxygen octahedral rotations in perovskite-structure EuTiO3
• Magnetodielectric coupling and phonon properties of compressively strained EuTiO3 thin films deposited on LSAT

Cited by in corpus (26)

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• Intrinsic Structural Disorder and the Magnetic Ground State in Bulk EuTiO3
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• Phonon Softening and Dispersion in EuTiO3
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• New multiferroics based on EuxSr1-xTiO3 nanotubes and nanowires
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• Correlating magnetic structure and magnetotransport in semimetal thin films of Eu${}_{1-x}$Sm${}_x$TiO${}_3$
• Size effect of soft phonon dispersion law in nanosized ferroics
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• Magnetic and dielectric properties of multiferroic Eu0.5Ba0.25Sr0.25TiO3 ceramics
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• Magnetic interactions and the puzzling absence of any Raman mode in EuTiO3
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