Research was focused on the preparation of compounds based on complex transition metal oxides (such as bismuth ferrites or manganites) in form of nanopowders, thin films, and ceramics. The important issue was to prepare single phase materials and to perform characterization of their crystal structure depending on the preparation technique, chemical composition, and environment (temperature, electric and magnetic field, etc.). The obtained compounds were characterized in terms of their functional properties as well as the correlation between the crystal structure, morphology, and physical properties depending on the preparation methods.
Multiple series of powders, ceramics, and thin films were prepared for studies. Samples were fabricated using solid-state, sol–gel, precipitation, or combustion methods. Various techniques were used to describe their properties. Samples were attested by XRD, electron microscopy techniques, termogravimetric analysis, and spectroscopic methods. Other specific approaches were used to look at some particular features of selected samples. For example, atomic resolution scanning transmission electron microscopy was used to explore the atomic structure. Local electromechanical measurements were performed via piezoresponse force microscopy. The same technique was used to study domain structure before and after local polarization reversal caused by stress in ceramics. The conductivity was studied using a scanning probe microscopy approach at the nanoscale level. Finally, synchrotron X-ray and neutron powder diffraction measurements were used to investigate more precisely the structures.
The problem of obtaining pure phase BiFeO3-based compounds is very widely displayed in the literature. Interest to these materials is related to their unique functional properties, and especially to the changes in these properties that occur when the material's crystal structure is modified. Such changes are particularly dependent on the size of the nanocrystals, which influences the temperature of the transformations and the ways they occur.
An important issue was also upscaling because modification of synthesis condition (as higher amounts of reagents) may cause change of phase composition. Therefore, fabrication of bigger amount of compounds was also tested to show the availability to move techniques to the (pre)industrial scale.
The Project participants consolidated the knowledge about obtaining ferroic materials and investigated the influence of chemical (e.g. composition, organic matrix used in sol–gel method, and fuel type in self-combustion method) and physical (e.g. temperature and annealing time or external stimuli) factors on compound properties (particle size, crystal structure, magnetization, piezoresponse, etc.). The main research was focused on the compounds having chemical compositions near to the morphotropic phase boundary regions where an improvement of functional properties is observed.
Research conducted under the TransFerr project was broadly presented in scientific articles – 63 papers were published in journals. The articles covered all aspects of the project studies. Participants were showing the results in over 80 conference presentations. Project topic was included in workshops and lectures given to students at Universities in Vilnius, Kiev, Aveiro, Gomel, Minsk, and Herrsching. We were also present during events dedicated to the general public, such as, Lower Silesian Science Festival, Doors Open Day for Youth, or Belarusian Science Day.
Details of the project activities can be followed through the Project website:
http://transferr.eu/(s’ouvre dans une nouvelle fenêtre)
