ACADEMICIAN EMIL DJAKOV INSTITUTE OF ELECTRONICS
BULGARIAN ACADEMY OF SCIENCES
72, Tzarigradsko chaussee blvd, 1784-Sofia, Bulgaria

 

LABORATORY MICROWAVE MAGNETICS

ÁÃ-åçèêEnglish
   
Activities Staff Publications Projects Posters

    

RESEARCH ACTIVITIES

Microwave Magnetics Laboratory - MWM

Throughout long years of research, the Microwave Magnetics (MWM) Laboratory at the Institute of Electronics, Bulgarian Academy of Sciences, has accumulated rich experience on the preparation and investigation of magnetic materials, mainly ferroxides with spinel and hexagonal structure (powders, thin and thick films, bulk materials, layered materials, hybrid structures, composites) and their application in microwave components. Based on gsoft chemistryh techniques, a number of methodologies, such as single microemulsion, sol-gel auto-combustion and sonochemical co-precipitation, have been developed for preparation of complex nanosized oxides, thick layers, ferrofluids and composite materials. The team has also experience in the characterization of the structural, magnetic, magneto-electric and microwave properties of these materials. The research carried out is of complex nature, including technological solutions on fabrication of materials, measurements of physical parameters and functional measurements geared to specific applications. Most of the structures have been prepared for application in MW components, particularly as MW absorbers and antireflection coatings. Recently, the main teamfs research effort has been focused on studying multiferroic materials based on M-, Y- and Z-type hexaferrites. The studies deal with determining these materialsf structural properties and understanding the magneto-electric effect in them. The Laboratory staff has also been involved in the investigations of biogenic magnetic materials for applications in ecology, in particular, studies on iron oxides produced as a result of natural biological processes. Another project carried out in conjunction another IE laboratory consists in a complex study of particulate matter in the atmospheric bio-aerosol after lidar localization of its time-space distribution . characterization by composition, structure, morphology and microbial content

The systems under study comprise:
- nanosize magnetic oxides - MexFe3-xO4, M-type hexaferrites (BaMexFe12-xO19)
- magnetic nanocomposites for microwave application
- ferrofluids
- biogenic oxides/hydroxides
- particulate matter in atmospheric bio-aerosol.
Equipment
The MWM laboratory has a well-equipped chemical laboratory for synthesis of magnetic materials, a setup for thick-films deposition from a suspension in an external magnetic field:
- Ultrasonic processor (Sonics-750 W);
- Ovens and high-temperature (up to 1500 °Ñ) tubular furnaces (Carbolite);
- Spin-spray coater;
- Equipment for measuring the MW properties of materials;
- Network Analyzer HP 8756 NA;
- DSP Gaussmeter 475 (LakeShore);
- Multiferroic tester (Radiant Technology) – advanced equipment for measurements of multiferroic materials;
- Digital binocular microscope (OPTIKA B-150DB);
- Stereo microscope type STEMI 305 (ZEISS);
- Cascade impactor type FSC-A6;
- Planetary mill (Fritsch pulverisette-2829);
- Vibratory mill (Fritsch pulverisette 1418);
- Uniaxial press (Pmax ~ 40 MPa);
- Diamond cutter Minosecar 2;
- Polishing equipment.
Y-type hexaferrite powders

Fig. 1 SEM image of magneto-electric Y-type hexaferrite powders synthesized by sonochemistry

 Z-type hexaferrite

Fig. 2. Reflection losses of composite samples with different Z-type hexaferrite filler ratio an external magnetic field applied.

    

    

    

Close window Top