| CZECH NANO TEAM | Physics of Nanostructures and Nanotechnologies

Author and co-author of about 240 publications in refereed journals (including 35 invited papers and review articles and 150 joint publications with foreign laboratories) with about 1500 citations (auto-citations subtracted).

Fellowships abroad:

• 1965 (6 months): University of Moscow1973 (10 months): ETH Zürich

• 1976 (10 weeks): J. Stefan Institute, Ljubljana

• 1983 (3 months): University of Nebraska, Lincoln

• 1985 (3 months): University of Saarbrücken1992 (2 months): ETH Zürich

• 1991-93 (3x1 month): EPF Lausanne

• 1999 (2 months): University of Aveiro

Solved projects since 1990:

4 grants given by GAČR, 2 by GAAV, 2 by COST (OC514.10 and 515.20), 2 by KONTAKT (with Moscow and Ljubljana), 2 by DFG (together with German partners from University of Stuttgart and Osnabrueck)).

Selected publications from last 3 years:

• J. Petzelt, T. Ostapchuk: Far-infrared ferroelectric soft mode spectroscopy on thin films, Ferroelectrics 249, 81-88 (2001)

• J. Petzelt, T. Ostapchuk, I. Gregora, I. Rychetský, S. Hoffmann-Eifert, A. V. Pronin, Y. Yuzyuk, B. P. Gorshunov, S. Kamba, V. Bovtun, J. Pokorný, M. Savinov, V. Porokhonsyy, D. Rafaja, P. Vaněk, A. Almeida, M. R. Chaves, A. A. Volkov, M. Dressel, R. Waser: Dielectric,infrared and Raman response of undoped SrTiO3 ceramics: Evidence of polar grain boundaries, Phys. Rev. B 64, 184111-1-184111-10 (2001)

• J. Hlinka, J. Petzelt, B. Březina, R. Currat: Phason dispersion in deuterated thiourea by inelastic neutron scattering, Phys. Rev. B 66, 132302-1/4 (2002)

• I. Rychetský, J. Petzelt, T. Ostapchuk: Grain-boundary and crack effects on the dielectric response of high-permittivity films and ceramics, Appl. Phys. Lett. 81, 4224-6 (2002)

• T. Ostapchuk, J. Petzelt, V. Železný, A. Pashkin, J. Pokorný, I Drbohlav, R. Kužel, D. Rafaja, B. P. Gorshunov, M. Dressel, Ch. Ohly, S. Hoffmann-Eifert, R. Waser: Origin of soft-mode stiffening and reduced dielectric response in SrTiO3 thin films, Phys. Rev. B 66, 235406-1/12 (2002)

• J. Petzelt. P. Kužel, I. Rychetský, A. Pashkin, T. Ostapchuk: Dielectric response of soft modes in ferroelectric thin films, Ferroelectrics 288, 169-185 (2003)

• J. Hlinka, S. Kamba, J. Petzelt, J. Kulda: Origin of the waterfall effect in phonon dispersion of relaxor perovskites, Phys. Rev. Lett. 91, 107602 (2003)

Group members:

Jan Petzelt, Milada Glogarová, Vladimír Železný, Stanislav Kamba, Přemysl Vaněk, Ivan Gregora, Petr Kužel, Jan Kroupa, Viktor Bovtun, Vladimíra Novotná, Elena Buixaderas, Ivan Rychetský, Jiří Hlinka, Alexej Bubnov

Main Research Subjects:

Broad-band dielectric spectroscopy (102-1014 Hz) and Raman and micro-Raman spectroscopy of high-permittivity dielectric ceramics, nano-grained ceramics, thin films, superlattices, composites, nano-composites, and liquid crystals compared, where available, with analogical single crystal properties. Effect of grain boundaries, grain shape and size and other defects. Development and application of suitable effective-medium theories. Study of size effects on ferroelectricity and related problems.

Selected Specific Equipment:

• Impedance analyzers HEWLETT-PACKARD 4192A, and SOLARTRON 1260, frequency range 1 Hz – 32 MHz, 10 – 800 K.

• Impedance analyzer AGILENT 4291B, frequency range 1 MHz – 1.8 GHz, coaxial technique, 100 – 550 K

• Microwave waveguide line for 10 and 35 GHz, temperature range 100 – 550 K suitable for dielectric measurements of bulk high-permittivity materials.

• Apparatus for time domain (femtosecond pulsed) THz spectroscopy, Ti:sapphire laser, spectral range 5 – 80 cm-1 (150 – 2400 GHz), temperature range 5 – 800 K, complex transmittance mode, complex reflectance mode available at room temperature, cryogenic measurements in preparation.

• Fourier spectrometer BRUKER IFS113v, spectral range 15-10.000 cm-1, temperature range 5 – 800 K, transmission and specular reflection measurements (two instruments).

• Raman spectrometer in visible light (Ar and Kr lasers), double-grating monochromator SPEX 14018, temperature range 5 – 800 K.

• Micro-Raman spectrometer RENISHAW Ramanscope, system 1000, multichannel detection, temperature range 100 – 800 K, polarizing microscope.
• Apparatus for second harmonic generation, pulsed Nd:YAG laser, temperature range 5 800 K

Additional recent selected publications by group members:

• I. Rychetský, D. Pociecha, V. Dvořák, J. Mieczkowski, E. Gorecka, M. Glogarová: Dielectric behavior of ferroelectric liquid crystals in the vicinity of the transition into the hexatic phase, Journal of Chemical Physics 111, 1541-1550 (1999)

• V. Novotná, M. Glogarová, V. Hamplová, M. Kaspar: Re-entrant ferroelectric phases in binary mixtures of ferroelectric and antiferroelectric homologues of a series with three chiral centers, Journal of Chemical Physics 115, 9036-9041 (2001)

• J. Hlinka, I.Gregora, V. Vorlíček: Complete spectrum of long wavelength phonon modes in Sn2P2S6 by Raman scattering, Phys. Rev. B 65, 064308-1/9 (2002)

• H. Němec, F. Kadlec, P. Kužel: Methodology of optical pump-terahertz probe experiment: an analytical frequency-domain approach, Journal of Chemical Physics 117, 8454 (2002)

• I. Rychetský, M. Glogarová, V.Novotná: Competition between the chiral smectic-C* and hexatic phases, Phys. Rev. E 67, 021704 (2003)

• A. Pashkin, M. Kempa, H. Němec, F. Kadlec, P. Kužel: Phase-sensitive time-domain terahertz reflection spectroscopy, Rev. Sci. Instrum. 74, 4711-4717 (2003).