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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Combined theoretical and nanoscale experimental study of Pb(Ca,Ba) TiO3, Pb(Sr,Ba)TiO3, and Pb(Sr,Ca)TiO3 complex perovskite structures: An investigation of the ferroelectric and electronic properties

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Autor(es):
Pontes, D. S. L. ; Bastos, W. B. ; Chiquito, A. J. ; Longo, E. ; Pontes, F. M.
Número total de Autores: 5
Tipo de documento: Artigo Científico
Fonte: Journal of Alloys and Compounds; v. 702, p. 327-337, APR 25 2017.
Citações Web of Science: 1
Resumo

Combined experimental and first-principles studies have been conducted to obtain a fundamental understanding of the effect of A-site chemical doping on the electronic structure and ferroelectric behavior of Pb(Ca,Ba)TiO3, Pb(Sr,Ba)TiO3, and Pb(Sr,Ca)TiO3 perovskite complex solid solutions. Rietveld refinement of powder X-ray diffraction data shows that the crystal structure of all the three compounds is distorted from the ideal cubic perovskite structure. At the nanoscale, piezoresponse force microscopy (PFM) studies show low-performance ferroelectric properties of Pb(Sr,Ca)TiO3 thin films when compared to Pb(Ca,Ba)TiO3 and Pb(Sr,Ba)TiO3 films. Theoretical analysis of the electronic band structure performed on the basis of density functional theory (DFT) allows to elucidate the origin of the different ferroelectric behaviors observed in Pb(Ca,Ba)TiO3, Pb(Sr,Ba)TiO3, and Pb(Sr,Ca)TiO3 thin films. DFT-based computational calculations reveal that there is a strong correlation between the effects of Ti 3d non-bonding orbitals (responsible for pi Ti-O bonding) and the ferroelectric polarization behavior of A(A'A{''})BO3 complex perovskite solid solutions. In our study, very low Ti 3d(xy,) d(xz), and d(y), non-bonding electronic density state contributions were observed and the presence of mainly ionic Ca-O and Sr-O bonds. These effects are the reason for the unusually weak polarization, low tetragonality, and poor ferroelectricity of Pb(Sr,Ca)TiO3 thin films. This is in contrast to the observed behaviors of Pb(Ca,Ba)TiO3 and Pb(Sr,Ba)TiO3 thin films. However, our first-principles calculations agree well with the PFM-based experimental results obtained in the nanometer scale. (C) 2017 Published by Elsevier B.V. (AU)

Processo FAPESP: 11/20536-7 - Materiais ferroelétricos multifuncionais: estudos das propriedades ópticas, elétricas e fotoluminescente
Beneficiário:Debora da Silva Lima Pontes
Linha de fomento: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
Beneficiário:Elson Longo da Silva
Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
Processo FAPESP: 12/14106-2 - Designe de óxidos multifuncionais com arquitetura perovskite (Pb,Sr,La, Bi) (Ti,Fe) O3
Beneficiário:Fenelon Martinho Lima Pontes
Linha de fomento: Auxílio à Pesquisa - Regular