Phase competition and effect of chemical ordering in ferroelectric relaxor PbSc0.5Nb0.5O3 from first principles

M. Paściak; T. R. Welberry; J. Hlinka

doi:10.1080/01411594.2016.1201824

Phase competition and effect of chemical ordering in ferroelectric relaxor PbSc_0.5Nb_0.5O₃ from first principles

M. Paściak^*, T. R. Welberry, J. Hlinka

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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Abstract

We present results of first principles calculations for ferroelectric relaxor PbSc_0.5Nb_0.5O₃. An ordered supercell with Sc and Nb atoms alternating in all directions (NaCl-like superstructure) has a ferroelectric ground state with R3 spacegroup. It is characterized by a tilt system a⁻a⁻a⁻ as well as different sizes of adjacent oxygen octahedra. Analysis of phonon instabilities in cubic (Formula presented.) reveals similarity with an antiferroelectric PbZrO₃. This is further confirmed by the fact that possibly antiferroelectric P2₁/b structure of PbSc_0.5Nb_0.5O₃ (symmetry lowered from Pbam due to Sc/Nb superstructure) is energetically very close to the ground state. The ferroelectric order is shown to be less sensitive to deviations in the B-site distribution than the antiferroelectric one.

Original language	English
Pages (from-to)	777-784
Number of pages	8
Journal	Phase Transitions
Volume	89
Issue number	7-8
DOIs	https://doi.org/10.1080/01411594.2016.1201824
Publication status	Published - 2 Aug 2016

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title = "Phase competition and effect of chemical ordering in ferroelectric relaxor PbSc0.5Nb0.5O3 from first principles",

abstract = "We present results of first principles calculations for ferroelectric relaxor PbSc0.5Nb0.5O3. An ordered supercell with Sc and Nb atoms alternating in all directions (NaCl-like superstructure) has a ferroelectric ground state with R3 spacegroup. It is characterized by a tilt system a−a−a− as well as different sizes of adjacent oxygen octahedra. Analysis of phonon instabilities in cubic (Formula presented.) reveals similarity with an antiferroelectric PbZrO3. This is further confirmed by the fact that possibly antiferroelectric P21/b structure of PbSc0.5Nb0.5O3 (symmetry lowered from Pbam due to Sc/Nb superstructure) is energetically very close to the ground state. The ferroelectric order is shown to be less sensitive to deviations in the B-site distribution than the antiferroelectric one.",

keywords = "Relaxor ferroelectrics, antiferroelectricity, first principles, soft modes",

author = "M. Pa{\'s}ciak and Welberry, {T. R.} and J. Hlinka",

note = "Publisher Copyright: {\textcopyright} 2016 Informa UK Limited, trading as Taylor & Francis Group.",

year = "2016",

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doi = "10.1080/01411594.2016.1201824",

language = "English",

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TY - JOUR

T1 - Phase competition and effect of chemical ordering in ferroelectric relaxor PbSc0.5Nb0.5O3 from first principles

AU - Paściak, M.

AU - Welberry, T. R.

AU - Hlinka, J.

PY - 2016/8/2

Y1 - 2016/8/2

N2 - We present results of first principles calculations for ferroelectric relaxor PbSc0.5Nb0.5O3. An ordered supercell with Sc and Nb atoms alternating in all directions (NaCl-like superstructure) has a ferroelectric ground state with R3 spacegroup. It is characterized by a tilt system a−a−a− as well as different sizes of adjacent oxygen octahedra. Analysis of phonon instabilities in cubic (Formula presented.) reveals similarity with an antiferroelectric PbZrO3. This is further confirmed by the fact that possibly antiferroelectric P21/b structure of PbSc0.5Nb0.5O3 (symmetry lowered from Pbam due to Sc/Nb superstructure) is energetically very close to the ground state. The ferroelectric order is shown to be less sensitive to deviations in the B-site distribution than the antiferroelectric one.

AB - We present results of first principles calculations for ferroelectric relaxor PbSc0.5Nb0.5O3. An ordered supercell with Sc and Nb atoms alternating in all directions (NaCl-like superstructure) has a ferroelectric ground state with R3 spacegroup. It is characterized by a tilt system a−a−a− as well as different sizes of adjacent oxygen octahedra. Analysis of phonon instabilities in cubic (Formula presented.) reveals similarity with an antiferroelectric PbZrO3. This is further confirmed by the fact that possibly antiferroelectric P21/b structure of PbSc0.5Nb0.5O3 (symmetry lowered from Pbam due to Sc/Nb superstructure) is energetically very close to the ground state. The ferroelectric order is shown to be less sensitive to deviations in the B-site distribution than the antiferroelectric one.

KW - Relaxor ferroelectrics

KW - antiferroelectricity

KW - first principles

KW - soft modes

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U2 - 10.1080/01411594.2016.1201824

DO - 10.1080/01411594.2016.1201824

M3 - Article

SN - 0141-1594

VL - 89

SP - 777

EP - 784

JO - Phase Transitions

JF - Phase Transitions

IS - 7-8

ER -

Phase competition and effect of chemical ordering in ferroelectric relaxor PbSc_0.5Nb_0.5O₃ from first principles

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