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Projects / Programmes source: ARIS

Dielektriki in kalorimetrija kondenzirane snovi (Slovene)

Periods
January 1, 1999 - December 31, 2003
Research activity

Code Science Field Subfield
1.02.00  Natural sciences and mathematics  Physics   

Code Science Field
P190  Natural sciences and mathematics  Mathematical and general theoretical physics, classical mechanics, quantum mechanics, relativity, gravitation, statistical physics, thermodynamics 
P250  Natural sciences and mathematics  Condensed matter: structure, thermal and mechanical properties, crystallography, phase equilibria 
P260  Natural sciences and mathematics  Condensed matter: electronic structure, electrical, magnetic and optical properties, supraconductors, magnetic resonance, relaxation, spectroscopy 
Evaluation (rules)
source: COBISS
Researchers (5)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  04347  PhD Cene Filipič  Physics  Researcher  2001 - 2003 
2.  10124  PhD Zdravko Kutnjak  Physics  Researcher  2001 - 2003 
3.  00199  PhD Adrijan Levstik  Physics  Head  2001 - 2003 
4.  03412  Ivana Levstik  Physics  Researcher  2001 - 2003 
5.  22328  PhD Boris Vodopivec  Physics  Researcher  2002 - 2003 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0106  Jožef Stefan Institute  Ljubljana  5051606000  18 
Abstract
The program includes investigations of - physics of disordered or partially ordered systems: relaxors and spin glasses - heat capacity of condensed matter - dielectric properties of the quantum nanomagnet Mn12acetate - dielectric properties of a human tooth. Correlations between the ferroelectric fatigue and variations in mechanical properties will be investigated in thick film 8/65/35 PLZT ceramics. Preliminary measurements show that fatigue in the bulk material reflects itself in dielectric and piezoelectric properties, while elastic compliances remains almost unchanged. The dynamics of the polar nanoclusters, the freezing of the dynamic process, and the electric field-temperature phase diagram of 9/65/35 PLZT ceramics will be studied by measurements of the frequency dependent dielectric constant as a function of the temperature and electric field. These investigations should reveal the mechanism responsible for the relaxor freezing process and the nature of the aging process. Latter could lead to the improvement of the properties important for the commercial applications. Recent dielectric relaxation studies in the protein lysozyme suggested a behavior typical of proton glasses. This hypothesis will be checked by the dielectric dispersion measurements in the frequency range 1 mHz-1 MHz and analysis of the results using temperature-frequency plot. High resolution calorimeter will be constructed. Heat capacity measurements enable studies of the energy fluctuations and enthalpy changes at the phase transitions. Liquid crystals with hexatic phases and mixtures of liquid crystals with aerogels will be investigated. The relaxation processes of magnetic moments in the quantum nanomagnet Mn12acetate will be investigated by measurements of the temperature and frequency dependent dielectric constant in the temperature range 4-20 K. Results should enable to explain the magnetic processes, which were observed below 3 K and could be the result of the quantum tunneling of the magnetic dipole moments. The diffusion of the Ag+ ions in a human tooth will be studied by measurements of the frequency dependent dielectric constant as a function of time and electric field. Results will be explained using a model developed for the cement hydration. The filling of the dentin channels with Ag using dc electric field could prevent microbes access into teeth.
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