”Monte Carlo modeling of domain structures and switching properties in ferroelectric ceramics”, financed by the Romanian National Authority for Scientific Research, CNCS – UEFISCDI

Nr. contract: PD 160/2018

Code: PN-III-P1-1.1-PD-2016-1069

Project Director: Asist. univ. dr. Leontin PADURARIU
(Faculty of Physics, Alexandru Ioan Cuza University, Iași)

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Ferroelectrics are multifunctional materials with a large applicability in microelectronics. The main characteristic of ferroelectrics is that, below a critical temperature (Curie temperature), they present spontaneous polarization and domain structure. This feature represents the physical origin of all macroscopic properties of ferroelectrics: switching (memory), nonlinear dielectric properties, piezoelectric, pyroelectric and electrooptic properties. Experimentally, it was demonstrated that ferroelectric domain structures are affected by many factors as: electrical and mechanical boundary conditions, average size of grains and boundaries in ceramics, the concentration and nature of the dopants in solid solutions, microstructural particularities in composites etc. Therefore, new materials with improved functional properties will be able to be produced, only by understanding the way these factors influence the domain structures. This goal can be achieved only by a modeling/simulation approach. In the last years, an intense research was dedicated in developing theoretical models able to describe properties of ferroelectrics at limited length scales, but a real breakthrough in the field would be realized by integrating these approaches into a complex multiscale model. The major objective of the project is to develop an innovative multiscale Monte Carlo model integrating Landau-Ginzburg-Devonshire theory and Finite Element Method, aimed to provide a powerful tool for describing ferroelectric properties of polycrystalline ceramics under realistic electrical and mechanical boundary conditions. During the project, the Monte Carlo model will be used to describe different fundamental problems of ferroelectricity: grain size effects, compositional effects in chemically inhomogeneous systems and microstructural effects in composites.

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The major objective of the project is to develop a complex Monte Carlo Method (based on Landau-Ginzburg-Devonshire theory and Finite Element Method) capable of describing domain structures and switching properties in ferroelectric ceramics in order to understand the role of geometrical, electrical and elastic parameters on their functional properties. The specific objectives are: (i) modeling of the ceramic effects in ferroelectric materials, (ii) investigation of the compositional effects in ferroelectric ceramics, (iii) study of the microstructural effects in ferroelectric-based composites.

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Expected results: Based on modeling approach, new methods of tailoring functional properties in ferroelectric ceramics by engineering local strains, charges and local electric field (material design) will be proposed. The deliverables of the project are:

- a model able to describe domain growth and local electric fields in ceramics;

- a model able to describe switching properties in ferroelectric ceramics with different grain sizes;

- a model capable to describe switching properties in ferroelectric based composites with different microstructural characteristics;

- scientific reports;

- ISI publications;

- oral presentations at international conferences.

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ISI publications

• N. Horchidan, L. Padurariu, C.E. Ciomaga, L. Curecheriu, M. Airimioaei, F. Doroftei, F. Tufescu, L. Mitoseriu, Room temperature phase superposition as origin of enhanced functional properties in BaTiO₃ - based ceramics, J. Eur. Ceram. Soc.,40, 1258-168 (2020). Available online from 2019. Impact factor: 4.495, TOP I (accordingly to UEFISCDI classification). This work was realized in collaboration for experimental part with the UEFISCDI project PN-III-P4-ID-PCE-2016-0817. https://www.sciencedirect.com/science/article/pii/S0955221919308441.
• L. Padurariu, V.A. Lukacs, G. Stoian, N. Lupu, L. Curecheriu, Scale-Dependent Dielectric Properties in BaZr_0.05Ti_0.95O₃ Ceramics, Materials, 13, 4386 (2020), Impact factor: 3.057, Yellow area (accordingly to UEFISCDI classification). This work is fully reported at this project.https://www.mdpi.com/1996-1944/13/19/4386
• L. Padurariu, C. Enachescu, L. Curecheriu, L. Mitoseriu, Why pyroelectric response is higher at Orthorhombic-Tetragonal than at Tetragonal-Cubic phase transformation in BaTiO3-based ceramics? Manuscript in prepartion. Expected year of publication: 2021. This work is realized in collaboration for experimental part with the UEFISCDI project PN-III-P1-1.1-TE-2019-1689.

Presentations at international conferences:

• L. Padurariu, I. Turcan, V.A. Lukacs, A. Cernescu, L. Curecheriu, C. Ciomaga, G. Stoian, N. Lupu, L. Mitoseriu, The Role of Composition on the Dielectric and Ferroelectric Properties of Ag-BaTiO₃ Composites: Experiment and Modeling, poster presentation at the conference Joint ISAF-ICE-EMF-IWPM-PFM, organized in Lausanne, Switzerland, in the period 14-19 July 2019. This work was realized in collaboration with the UEFISCDI project PN-III-P4-ID-PCE-2016-0817. https://conf.papercept.net/conferences/conferences/ISAF19/program/ISAF19_ProgramAtAGlanceWeb.html
• L. Padurariu, C. Enachescu, L. Mitoseriu, Modeling of the Grain Size Effects in Nanostructured Ferroelectric Ceramics, oral presentation at the conference Processes In Isotopes And Molecules organized in Cluj-Napoca, Romania, in the period 25-27 September 2019. http://pim.itim-cj.ro/pages/programme.html
• L. Padurariu, C. Enachescu, L. Mitoseriu, Modeling of the Grain Size Effects in Nanostructured Ferroelectric Ceramics, oral presentation at the conference Asian Advanced Materials Congress, organized in Singapore in the period 31 October - 4 November 2019. https://www.advancedmaterialscongress.org/nov19/pages/program
• L. Padurariu, N. Horchidan, M. Airimioaei, L. Curecheriu, C. Ciomaga, L. Mitoseriu, Room temperature phase superposition of barium titanate- based ceramics: modeling and experimental validation, oral presentation at the conference Electroceramics XVII organized in Darmstadt, Germany, in the period 24-28 August 2020. https://www.electroceramics.org/en/electroceramics-xvii/welcome.html

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Reports:

2018 (in Romanian)

2019 (in Romanian)

2020 - Final report (in Romanian)

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