1. 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
- Author
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Adenilson J. Chiquito, F. M. Pontes, W.B. Bastos, D.S.L. Pontes, Elson Longo, Universidade Federal de São Carlos (UFSCar), and Universidade Estadual Paulista (Unesp)
- Subjects
Materials science ,Rietveld refinement ,Thin films ,Mechanical Engineering ,Piezoresponse force microscopy ,Metals and Alloys ,Analytical chemistry ,Ionic bonding ,Mineralogy ,02 engineering and technology ,Crystal structure ,Perovskite ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ferroelectricity ,0104 chemical sciences ,First-principles calculations ,Mechanics of Materials ,Materials Chemistry ,0210 nano-technology ,Electronic band structure ,Solid solution ,Perovskite (structure) - Abstract
Made available in DSpace on 2018-12-11T17:31:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) 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)TiO3perovskite 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)TiO3thin films when compared to Pb(Ca,Ba)TiO3and Pb(Sr,Ba)TiO3films. 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)TiO3thin films. DFT-based computational calculations reveal that there is a strong correlation between the effects of Ti 3d non-bonding orbitals (responsible for π Ti[sbnd]O bonding) and the ferroelectric polarization behavior of A(A′A″)BO3complex perovskite solid solutions. In our study, very low Ti 3dxy,dxz, and dyznon-bonding electronic density state contributions were observed and the presence of mainly ionic Ca[sbnd]O and Sr[sbnd]O bonds. These effects are the reason for the unusually weak polarization, low tetragonality, and poor ferroelectricity of Pb(Sr,Ca)TiO3thin films. This is in contrast to the observed behaviors of Pb(Ca,Ba)TiO3and Pb(Sr,Ba)TiO3thin films. However, our first-principles calculations agree well with the PFM-based experimental results obtained in the nanometer scale. LIEC – CDMF- Department of Chemistry Universidade Federal de São Carlos, Via Washington Luiz, Km 235, P.O. Box 676 NanO LaB – Department of Physics Universidade Federal de São Carlos, Via Washington Luiz, Km 235, P.O. Box 676 Department of Chemistry Universidade Estadual Paulista - Unesp, P.O. Box 473 LIEC- CDMF-Institute of Chemistry Universidade Estadual Paulista – Unesp Department of Chemistry Universidade Estadual Paulista - Unesp, P.O. Box 473 LIEC- CDMF-Institute of Chemistry Universidade Estadual Paulista – Unesp FAPESP: 11/20536-7 FAPESP: 12/14106-2 FAPESP: 13/07296-2 CNPq: 470147/2012-1
- Published
- 2017