Department of Radiophysics

Laboratory of Phase Transitions
Dielectric Spectroscopy

Heads

prof. Jonas Grigas
former head 1965-1999
 

assoc.prof. Juras Banys

Staff

Prof. DSc. Juras Banys
juras.banys@ff.vu.lt
Prof. DSc. Jonas Grigas
jonas.grigas@ff.vu.lt
Dr. Saulius Lapinskas
saulius.lapinskas@ff.vu.lt
Assoc. Prof. Dr. Algirdas Brilingas
PhD students

Main publications

1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006

The research in microwave dielectric spectroscopy of semiconductors in the Laboratory started in 1965. The Laboratory was established for studies of:

• Dielectric properties of semiconductors at frequencies above the Maxwell relaxation frequency,
• Low-frequency soft phonon modes which frequency lies below the limits of optical spectroscopy in ferroelectrics,
• Soft relaxation modes and relaxation dynamics in order-disorder ferroelectrics, ferroelectric ceramics, dipolar glasses and other solids.

Our Mission

• To promote research of phase transitions which excite extreme properties of materials,
• By radio and microwave dielectric spectroscopy to reveal and disseminate knowledge about phenomena in modern materials for telecommunication technologies.

The main subjects of research

• Design and manufacturing of microwave dielectric spectrometers,
• Phase transitions and microwave dielectric spectroscopy of :
  a) low-dimensional semiconductors Sb2S3, Sb2Se3, Bi2S3, etc.
  b) complex halcogenides,
  c) complex halogenides.
• Low-frequency soft phonon modes in semiconductors-ferroelectrics SbSI, SbSeI, SbSBr, Sn2P2S6, Sn2P2Se6, TlInS2, TlGaSe2, etc.
• Relaxational dynamics and phase transitions in quasi-one-dimensional H-bonded ferroelectrics CsH2PO4, RbD2PO4, PbHPO4, etc.
• Theoretical models of phase transitions,
• Relaxational dynamics and phase transitions in metaloorganic and other order-disorder ferroelectrics RbHSO4, DGN, TAAP, DMAAS, Betaines, etc.
• Relaxational dynamics and phase transitions in ferroelectric ceramics (PLZT, etc.).
• Relaxational dynamics and phase transitions in protonic conductors CsHSO4, CsHSeO4, Rb3H(SeO4)2, (NH4)H(SeO4)2, etc.
• Relaxational dynamics of and freezing phenomena in dipolar glasses and mezoporous systems.

Cooperation

• Institute of Physics, Czech Academy of Sciences (Prof. J.Petzelt, Dr. S.Kamba),
• Institute of Low Temperatures and Structure Research, Polish Academy of Sciences (Prof. K.Lukaszewicz),
• Leipzig University (Prof. G.Völkel, Prof. R.Böttcher , Prof. D.Michel, DSc. A.Pöppl),
• Uzhorod University (Prof. Yu.Vysochanskii),
• Latvian University (Prof. A.Sternbergs),
• Duisburg University (Prof. W.Kleemann),
• Wroclaw University (Prof. Z. Czapla).

Projects

• "Institute Partnershaft" Project between the Laboratory and Physik Dielektrische Festkörper Section, Leipzig University (2003 - 2006),
• 5th Framework Programme   No.G5RT-CT-2001-05024 "Polecer" (2003-2004),
• Grants from Lithuanian Science and Studies Foundation (2000-2004).

Equipment

The Laboratory possess the computer-controlled coaxial and waveguide spectrometers, including HP 4284A (20 Hz – 1 MHz) and Agilent 8714ET (300 kHz – 3 GHz) and other equipment, which cover the frequency band from 20 Hz to 120 GHz.

The following researchers defended PhD theses in Laboratory

J.Grigas (1968), A.Orliukas (1975), R.Beliackas (1979), J.Meskauskas (1979), A.Brilingas (1981), V.Kalesinskas (1983), V.Urbonavicius (1984), W.Paprotny (1985), K.Zickus (1987), J.Banys (1990), R.Mizeris (1991), V.Valevicius (1991), R.Sobiestijanskas (1993), and A.Kajokas (1999),

and DSc theses (habilitation)

J.Grigas (1980), A.Orliukas (1995), J.Banys (2000).

Contact Information

Telephone

(370 5) 2366077

 

FAX

(370 5) 2366081

 

Postal address

Sauletekio al. 9/3
10 222 Vilnius
LITHUANIA

 

Last modified: 2007 03 30
Webmaster: vytautas.jonkus@ff.vu.lt