The paper, which was published in a high-impact journal (Advanced Functional Materials, IF 11.805, source JCR), explains the complex relationship between the nanoscale electrical conductivity at domain walls in BiFeO3 and its macroscopic piezoelectric response. A combination of electromechanical measurements both at the nanoscale and macroscopic (millimeter) scale revealed that the conductivity localized at the ferroelectric and ferroelastic domain walls has a marking effect on the mobility of these walls and thus on the macroscopic piezoelectric behaviour. This new mechanism, referred to as the “nonlinear piezoelectric Maxwell-Wagner effect”, may be in principle present in ferroelectrics containing boundaries or interfaces that can both displace under external field and exhibit enhanced electrical conductivity (such as domain walls in BiFeO3). The paper is accompanied with an inside front cover authored by the researchers from the Electronic Ceramics Department K-5.
COBISS.SI-ID: 28359975
Literature on rare-earth (RE=Sm, Gd, Dy) modified BiFeO3 reports on a number of different phases, i.e., polar (R3c), nonpolar (Pnma or Pbnm) and antipolar (Pbam), forming in different amounts in dependence on the concentration of RE-oxide. In this paper, published in Acta Materialia (IF 4,465; source: JCR), we discuss how the synthesis of the (BiSm)FeO3 ceramics affects their phase composition, chemical homogeneity, and morphology and distribution of phases. To demonstrate this point, the study compares two ceramics prepared using different snythesis methods, i.e., conventional ceramic processing and mechanochemical activation. The reaction pathways during the two syntheses are different and this has a significant effect on the chemical composition and distribution of the antipolar (Pbam) phase in the sintered ceramics. Despite the large amount of publications on (BiSm)FeO3 ceramics, only a few discuss the synthesis-phase-composition relationship; our study thus reveals the important role of the synthesis on the properties of these ceramics, including the functional response.
COBISS.SI-ID: 28038439
The study presents the preparation of a ~15 micrometers-thick BFO film onto different substrates (Al2O3, Ag) using screen printing. We have identified the key parameters, i.e., the sintering temperature and the substrate purity, which must be controlled in order to obtain dense and microstructurally homogeneous BiFeO3 thick films with minimal concentration (~0.5 wt.%) of secondary phases. The results of this study represent an important step toward the integration of BiFeO3-reated materials onto substrates for sensor and actuator applications.
COBISS.SI-ID: 28779815