A new material design paradigm in electroceramics: charged defects engineering (ElectroChargEng)

Project code: PN-III-P1-1.1-TE-2019-1929
Project number: TE84/2020
Funded by the Executive Unit for Financing High Education, Research, Development and Innovation, CNCS – UEFISCDI (Oct. 2020 – Nov. 2022)


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.