a. Head of Group: Dra. Miriam S. Castro
b. The interests of the group focus on the development of new functional materials (ceramics and composites) with dielectric, magnetic, piezoelectric and magnetoelectric applications, from the structural and microstructural control of the active phases.
c. Ongoing projects.
The area of ceramic materials for applications in electronics started its activities within the Ceramic Division in 1988. Since that time zinc oxide, tin oxide and barium titanate-based materials for varistors, gas sensors, thermistors with positive temperature coefficient, and capacitors have been studied. Polymer-ceramic composites for electrical applications have also been analyzed. A further line of research has focused on the study of soft magnetic ceramics, including metal-ceramic composites (Fe/Al2O3) and cubic ferrites MnxZn1-xFe2O4 systems. In recent years, studies on the synthesis of orthoferrites YxLa1-xFeO3, SrxLa1-xFeO3, BixLa1-xFeO3 of technological interest for their use in areas of increasing interest such as fuel cells, sensors, magneto-optical materials and catalysts have been devoloped. Synthesis methods employed by the group include solid state reaction, mechanochemical activation, hydrothermal synthesis and sol-gel. The relationship between structure, microstructure and final properties is studied in detail for every developed material or device. Currently, the research focuses on the development of dielectric nanocomposites, nanostructured thin films, lead-free piezoelectric materials, BiFeO3-based multiferroic material and biphasic systems.
High-dielectric-constant ceramic-powder polymer composites. Development of new dielectric materials adding nanostructured fibres of BaTiO3 to a polymer matriz.
Nanostructured thin films. Design and evaluation of conducting films on insulating substrates to be used as electrodes, and dense films for capacitors and varistors.
Piezoelectric and relaxor ceramics. Development of lead-free ceramics based on the K1/2Na1/2NbO3 (KNN), Bi0.5(Na0.78K0.22)0.5TiO3 (BNKT), Bi0.5Na0.5TiO3 (BNT) and BaTiO3 systems with piezoelectric and relaxor behavior.
Magnetic ceramics. Synthesis of soft magnetic materials based on transition metal ferrites with aplications in electronic devices.
Multiferroic materials. Design of novel materials with magnetoelectric properties: single-phase and bi-phase (ferrimagnetic-piezoelectric) from the structural and microstructural control of the active phases.
FE-SEM image of the cross section of a Ti-ZnO film.
|Epoxy/BaTiO3 composite materials. Photograph of a cross section (a), SEM image of the lateral area (b). Inset in b) corresponds to a magnification of the marked region.|
SEM image of LaFeO3 nanocrystalline particles obtained, at temperature temperature, by mechanochemical activation.