Synthesis of Materials K8

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The research at the Materials Synthesis Department is devoted to the development of advanced oxide materials suitable for electromagnetic applications. The aim of our research is to obtain knowledge in materials chemistry for the controlled synthesis of new materials with desirable electromagnetic properties.

The obtained knowledge combined with an understanding of the tuning of materials’ chemical properties can be employed in the synthesis of composite and/or multifunctional materials. The department’s activities are focussed on materials for applications in electronics, telecommunications, medicine, and ecology.

MATERIALS SYNTHESIS – K8

  • magnetic nanomaterials: synthesis and functionalization of nanoparticles, magnetic fluids, magnetic nanocomposites,
  • multifunctional materials,
  • magnetic materials for micro- and mm-wave devices,
  • fluorescent materials,
  • semiconducting ceramics.

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Head of Department
Prof. Dr. Darko Makovec, darko.makovec@ijs.si
Telephone: +386 1 477 35 79

Secretary
Bernarda Anželak, bernarda.anzelak@ijs.si
Telephone: +386 1 477 33 23


Magnetic nanoparticles (magnetic fluids, nanocomposites)
New methods for the controlled synthesis of nanoparticles, i.e., spinel and hexagonal ferrites, are being developed. Additionally, we are focused on the functionalization of magnetic nanoparticles, primarily for biomedical applications. The surface properties of nanopowders, which determine their applicability, are tuned with inorganic coatings (i.e., a thin film of amorphous silica), with polymer coatings or with single-molecule layers (i.e., from various silanes). This provides the basis for a selective binding of various molecules (i.e., bioactive molecules) onto the nanoparticles' surfaces. At the same time, the coating prevents the agglomeration of nanoparticles, which further enables their dispersion in various liquids, i.e., magnetic fluids or the homogeneous incorporation of nanoparticles in various matrices.

Multifunctional materials
Nanocomposites with a combination of the various properties of the constituent materials can be prepared by mastering the surface properties of nanoparticles. Examples of our studies include combinations of ferrimagnetics and dielectrics (magnetodielectrics) and ferrimagnetic and ferroelectric (composite multiferroics) materials. Current studies are related to the development of new, magneto-optic materials. Here we are studying the mechanisms of magnetic-particle crystallization in various optically transparent matrices and the influence of the particles' magnetic properties and the applied magnetic field on the optical behaviour of the composites. These new materials represent the basis for new, advanced magneto-optic sensors. Photo-catalytic nanocomposite particles with a magnetic response are synthesized with a coating of titania nanoparticles onto titania nanoparticles and are used for the purification of polluted water and gases.

Magnetic materials for micro- and mm-waves
Magnetic materials suitable for the absorbers of electromagnetic waves and for non-reciprocal ferrite devices are being developed. We are working on solutions to ecological problems by studying absorbers, which can also be used for the reduction of microwave pollution. These studies involve synthesis, the chemistry of materials, and the characterization and correlation of the chemical and physical properties of materials. Ceramics and composites based on ferrites are studied for microwave applications, and a new method for the preparation of magnetically oriented thick hexaferrite films is under development for mm-wave applications.

Semiconducting ceramics
Mastering the composition and properties of grain boundaries in certain semiconducting ceramics (ZnO, BaTiO3) makes possible the preparation of materials with an electrical resistivity that is very dependent on the applied voltage (varistors) or on the operating temperature (resistors with the positive temperature coefficient of resistivity = posistors). For the latter, donor-doped ferroelectric BaTiO3 ceramics are under investigation. However, the main problem is the addition of lead, which increases the useful temperature of BaTiO3 ceramics. Our studies are also focused on new, lead-free materials (KNbO3, BaNb2O6) with high Curie temperatures.


J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, Telephone: +386 1 477 39 00, Fax: +386 1 251 93 85
info@ijs.si