Exploiting porosity in ferroelectric materials by local field engineering towards improved functional properties

Financed by the Romanian National Authority for Scientific Research, CNCS – UEFISCDI,
project PN-II-RU-TE-2014, no. 257 / 2015

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

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Ferroelectric-based composites are considered a better alternative to single phase ferroelectrics to accomplish the technological requirements for many applications in microelectronics. The electrical properties of such systems are governed by the inhomogeneity of the local electric field introduced by the interfaces between phases with different local permittivity. Among ferroelectric-based composites, in porous ferroelectric ceramics the local field inhomogeneity effect is maximized due to the huge permittivity contrast (1 for pores and thousands for bulk). Although porosity was generally considered undesired in ferroelectrics because is usually detrimental from functional properties point of view, when is not controlled, recent reports showed enhancement of some properties, which make very appealing a study aimed to a deeper understanding of porosity in electroceramics properties. Therefore, by local field engineering through microstructural control, porous ferroelectric present a great potential to accomplish the desired electrical properties in microelectronics. In the present project, by a multidisciplinary approach of modeling, preparation and electrical characterization, we propose to demonstrate the usefulness of local field engineering approach combined with advanced preparation methods for controlling the microstructures, in order to exploit porosity as a new tool for improving some specific functional properties of ferroelectrics

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The major objective of the project is to investigate by a complex modeling/experimental approach the role of porosity at various length scales and for different pore shapes on the functional properties of ferroelectric materials.

Specific objectives:

OI: Study of the role of porosity on tunability in porous paraelectric materials. Different types of porous materials will be described by modeling tools and the best configurations will be produced, experimentally investigated and compared to the modeling results:

OI.1 Modeling the tunability properties of porous ferroelectrics,

OI.2 Experimental study of the role of porosity on the low and high field properties of porous ferroelectrics in paraelectric state (e.g. BST, BZT, PMN ).

The expected scientific impact is related to: development of original multiscale models based on 3D FEM (at microscale level) and LGD theory (at mesoscale level), to describe the role of the microstructures on the nonlinear dielectric properties of porous ferroelectrics; understanding the relation between the porosity and effective properties through local field distortion at mesoscale. Novelty: a new approach in controlling the tunability properties by local field engineering and porosity control.

OII: Study of the role of porosity on the switching properties of porous ferroelectrics. The role of porosity on the switching properties at different length scales from nanoscale (lower than domain size) to microscale (larger than domain size) and various microstructures will be simulated by a complex multiscale approach (Monte Carlo and Preisach models to describe domain structures and switching properties at mesoscale and 3D FEM to describe local field inhomogeneity). The most interesting configurations will be selected to be produced, investigated and compared with simulations results:

OII.1 Modeling of the role of porosity on the switching properties of porous ferroelectrics.

OII.2 Experimental verification for porous ferroelectric ceramics (e.g. PZT, PMN-PT, BT) with different sizes and shapes of the pores.

The expected scientific impact: the contribution to understand the role of porosity on the properties of ferroelectrics at different length scales: domain structures, local hysteretic responses at mesoscale and macroscopic effective dielectric and ferroelectric properties.

OIII. Managerial objective. This objective includes: coordination of the research activity, dissemination activity (preparation and publication of ISI papers, presentations at international conferences, web-site, yearly scientific reports), acquisition of equipments and materials, etc.

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Reports:

2015 (in Romanian) (in English)

2016 (in Romanian)

2017(in Romanian)

Papers:

1. Comment on “The Impact of Composite Effect on Dielectric Constant and Tunability in Ferroelectric-Dielectric System”, L. Padurariu and L. Mitoseriu, J. Am. Ceram. Soc., 99 [11] 3816–3817 (2016) (Impact Factor =2.787)

2. Porosity-Dependent Properties of Nb-Doped Pb(Zr,Ti)O3 Ceramics, F. Gheorghiu, L. Padurariu, M. Airimioaei, L. Curecheriu, C. Ciomaga, C. Padurariu, C. Galassi, and L. Mitoseriu, J. Am. Ceram. Soc., 1–9 (2016) (Impact Factor =2. 787)

3. Role of the pore interconnectivity on the dielectric, switching and tunability properties of PZT ceramics, C. Padurariu, L. Padurariu, L. Curecheriu, C. Ciomaga, N. Horchidan, C. Galassi and L. Mitoseriu, Ceramics International, in press (Impact factor =2.758)

4. . Porous (Ba,Sr)TiO3 ceramics for tailoring dielectric and tunability properties: Modeling and experiment, R. E. Stanculescu, N. Horchidan, C. Galassi, M. Asandulesa, L. Padurariu, C. E. Ciomaga, and L. Mitoseriu, Processing and Application of Ceramics, in press (2017) (Impact factor =1.070)..

Conferences:

1. Modeling of the nonlinear dielectric properties of paraelectric-dielectric composites by a 3D Finite Element Method based on Landau-Devonshire theory, L. Padurariu, L. Mitoseriu, ElectroCeramics XV, 27-29 June 2016, Limonges, France (invited presentation)
2. Effect of porosity on ferroelectric-relaxor crossover in BaTiO3-based ceramics, L. Curecheriu, L. Padurariu, M.T. Buscaglia, V. Buscaglia, L. Mitoseriu, ElectroCeramics XV, 27-29 June 2016, Limonges, France (oral presentation)
3. Modeling of the nonlinear dielectric properties of paraelectric-dielectric composites by a 3D Finite Element Method based on Landau-Devonshire theory, L. Padurariu, L. Mitoseriu, ISAF/ECAPD/PFM Conference in Darmstadt, 21-25 August 2016 Germany (oral presentation)
4. Exploiting porosity for design tunable materials, L. Curecheriu, C. Padurariu, L. Padurariu, L. Mitoseriu, ISAF/ECAPD/PFM Conference in Darmstadt, 21-25 August 2016 Germany (oral presentation)
5. Modeling of the dielectric properties of porous ferroelectric structures, L. Padurariu, L. Curecheriu, R. Stanculescu, C. Ciomaga, C. Padurariu, C. Galassi and L. Mitoseriu, IC1208 Joint 8th Management Committee Meeting (MCM8) Meetings of Working Groups WG1–WG4, 8th-9th September 2016, Warsaw, Poland (oral presentation)
6. Tuning properties in electroceramics by composition and microstructural control, L.P. Curecheriu, L. Padurariu, L. Mitoseriu, COST Meeting IC1208 University of Luxembourg, March 16-17, 2017, Luxembourg (oral presentation)
7. Microstructure effects on low and high field dielectric properties of (Ba,Sr)TiO3 based porous solid solutions, R. Stanculescu, N. Horchidan, L. Padurariu, C. Galassi, M. Asandulesa, C.E. Ciomaga, and L. Mitoseriu, ECerS 2017 15th Conference &Exhibition of European Ceramic Society July 9-13, 2017, Budapest, Hungary (poster presentation)
8. Local field engineering for tailoring electrical properties in ferroelectric-based composites, L. Padurariu, L. Mitoseriu, ECerS 2017 15th Conference &Exhibition of European Ceramic Society July 9-13, 2017, Budapest, Hungary (invited presentation)
9. Effect of porosity on the dielectric, switching and DC-tunability properties of BaTiO₃ ceramics, L.P. Curecheriu, C. Padurariu, L. Padurariu, R. Stanculescu, N. Horchidan, C. Ciomaga, L. Mitoseriu, ECerS 2017 15th Conference &Exhibition of European Ceramic Society July 9-13, 2017, Budapest, Hungary (oral presentation)
10. Dielectric properties of porous ferroelectric structures: modeling and experimental verification, L. Curecheriu, L. Padurariu, C. Ciomaga, R. Stanculescu, C. Padurariu, M. Airimioaei, L. Mitoseriu, IEEE ROMSC 2017 14th edition, “Alexandru Ioan Cuza” University of Iasi, Romania, 26th of June 2017 Iasi, Romania (oral presentation)
11. Effect of porosity on the dielectric and dc-tunability properties of BaTiO₃ ceramics, L.P. Curecheriu, C. Padurariu, L. Padurariu, R. Stanculescu, C. Ciomaga and L. Mitoseriu, 11 th International Conference PROCESSES IN ISOTOPES AND MOLECULES, 27 - 29 September 2017, Cluj-Napoca, Romania (oral presentation)

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