Since single-phase ferroelectric materials cannot accomplish all the technological requirements in applications, developing composite materials that combine the properties of the ferroelectrics with other constituent phases (linear dielectrics, magnetic materials or other conductive/ semiconductor components) is a commonly proposed solution. Recently, it has been shown that a major factor that influences the effective properties of composite materials is the local electric field inhomogeneity introduced by the interfaces between the phases with different permittivities. Based on this effect, we proposed, through a complex modeling / experimental approach, the concept of local field engineering, which involves the design of materials with controlled microstructures and, implicitly, an optimum inhomogeneity of the electric field in order to improve the functional properties.

Another important factor that influences the functional properties of composites is the accumulation of free charges at interfaces, but this has been neglected so far in the local field engineering approaches proposed in literature because it involves important computational difficulties. In this project we propose to explore the influence of free electric charges on the effective dielectric properties of real composite systems (which exhibit dielectric losses) through a complex modeling/simulation and experimental validation approach for different types of composites (ferroelectric-semiconductor, magnetoelectric, porous ferroelectrics, etc.). After elucidating the mechanisms in which the free charges influence the functional properties of the composite systems, we propose to design and develop a dielectric-semiconductor composite material for energy storage applications. Within this project, the concept of charged defects engineering will be proposed as a generalization of the high impact idea of local field engineering, previously proposed by the research team.

Lect. Dr. Leontin Padurariu (director)
Prof. Dr. Liliana Mitoseriu
Lect. Dr. Habil. Lavinia-Petronela Curecheriu
Lect. Dr. Mirela Airimioaei
PhD Student: Vlad-Alexandru Lukacs
Master Student: Radu-Stefan Stirbu

The major objective of the project is to demonstrate that, contrary to the general belief that charged defects are detrimental for dielectric performances of ferroelectric-based electroceramics, a small level of charged defects can be a beneficial factor for improving some functional properties, if properly controlled by microstructural characteristics. Based on a combined modeling/experimental approach, this project proposes a new paradigm in material design: charged defects engineering. In order to achieve this goal, a novel dynamic FEM-based approach will be developed which will integrate the role of free charges and will be able to describe the complex effective dielectric properties (including the dielectric loss) in a broadband frequency range. In the first part of the project, the modeling approach will be used to describe the complex dielectric properties for different ferroelectric-based composites like magnetoelectric composites, porous materials si composite ferroelectric semiconductor. After this experimental validation, the modeling approach will be used as a tool to design novel materials with desired dielectric properties (e.g. for energy storage applications).

• A new modeling approach based on Finite Element Method which will be able to describe the free charges dynamic in electroceramics and complex dielectric properties
• A ferroelectric-semiconductor composite system which will serve as a model system for the modeling activity
• A specially designed ferroelectric-semiconductor composite with controlled microstructure for energy storage application
• ISI publications
• Presentations at international conferences
• Website

Report 2020-2022 - Final report (romanian) 

Oral presentations at international conferences:

1. Padurariu, L. Curecheriu , C. Ciomaga, L. Mitoseriu, Exploiting Local Field Inhomogeneity for Tunning Functional Properties in Ferroelectric Based Composites, 11^th International Advances in Applied Physics & Materials Science Congress & Exhibition, 13 – 16 October 2021, Oludeniz -Turkey (invited talk)
2. Padurariu, L. Curecheriu, V. Lukacs, M. Airimioaei, C. Ciomaga, L. Mitoseriu, Modeling the complex dielectric properties in ferroelectric-based composites by a dynamic finite element method, 13^th International Conference PROCESSES IN ISOTOPES AND MOLECULES, 22-24 September 2021, Cluj-Napoca, Romania
3. Padurariu, L. Curecheriu , C. Ciomaga, L. Mitoseriu, Dynamic Finite Element Method for describing complex dielectric properties in ferroelectric-based composites, 6^th edition of the International Workshop of Materials Physics, 14 -16 Sept. 2021, Magurele, Romania
4. Padurariu, L. Curecheriu, C. Ciomaga, L. Mioseriu. Modeling of the dielectric properties in ferroelectric-based composites by Finite Element Method, The 6^th International Symposium On Dielectric Materials and Applications (ISyDMA’6), 15-17 December 2021, Calais, France
5. Padurariu, L. Curecheriu, M. Airimioaei , V.A. Lukacs, R.S. Stirbu, L. Mitoseriu, Modeling of the dielectric properties in ferroelectric-based composites by a new dynamic finite element method, Ceramics in Europe, 10-14 July 2022, Krakow, Poland
6. Padurariu, L.P. Curecheriu, V.A. Lukacs, R.S. Stirbu, C.E. Ciomaga, M. Airimioaei, L. Mitoseriu, Describing complex dielectric properties in ferroelectric-based composites by a new dynamic finite element method, 14^th International Conference on Physics of Advanced Materials, 8-15 September 2022, Dubrovnik, Croatia

ISI publications:

1. Padurariu, L.P. Curecheriu, C.E. Ciomaga, M. Airimioaei, N. Horchidan, C. Cioclea, V.A. Lukacs, R.S. Stirbu, L. Mitoseriu, Modifications of structural, dielectric and ferroelectric properties induced by porosity in BaTiO3 ceramics with phase coexistence, JOURNAL OF ALLOYS AND COMPOUNDS, 889, 161699 (2021) – in collaboration with the project PN-III-P4-ID-PCE-2020-1988.
2. S. Stirbu, L. Padurariu, F.F. Chamasemani, R. Brunner, L. Mitoseriu, Mesoscale Models for Describing the Formation of Anisotropic Porosity and Strain-Stress Distributions during the Pressing Step in Electroceramics, MATERIALS, 15, 6839 (2022) – in collaboration with the project PN-III-P4-ID-PCE-2020-1988
3. Padurariu, N. Horchidan, C. E.Ciomaga , L. P. Curecheriu, V. A. Lukacs, R. S. Stirbu, G. Stoian, M. Botea, M. Florea, V. A. Maraloiu, L. Pintilie, A. Rotaru, L. Mitoseriu, The influence of ferroelectric filler size & clustering on the electrical properties of (Ag-BaTiO₃)-PVDF sub-percolative hybrid composites, ACS Applied Materials & Interfaces (in correction, but it received favorable initial review) – in collaboration with the project PN-III-P4-ID-PCCF-2016-0175
4. Padurariu, L. Mitoseriu, Dynamic Finite Element Method for describing complex dielectric properties in ferroelectric-based composites, SCRIPTA MATERIALIA (manuscript in evaluation)
5. Padurariu, E. Brunengob, G. Canu, L.P. Curecheriu, L. Conzatti , M. T. Buscaglia, P.Stagnaro, L. Mitoseriu, V. Buscaglia, The role of microstructure on the dielectric properties of PVDF-based nanocomposites for energy storage containing high-permittivity fillers (manuscript ready for submission to journals) - part of this research work was supported by the Bank Foundation Compagnia di San Paolo, Torino, Italy [Project “Polycom: Engineered polymeric composites with high energy density” (ID ROL: 10359)]
6. Padurariu, L.P. Curecheriu, M. Airimioaei, V.A. Lukacs, R.S. Stirbu, L. Mitoseriu, Functional properties and relaxation mechanisms in Ba(Zr,Ti)O₃-ZnO ceramic composites (manuscript in preparation)