ZB-20. Ferroelectrics and Liquid Crystals

 

 

Head of the Group: Prof. Ryszard Jakubas

M.Sc. 1975, Ph.D. 1980, D.Sc. 1989, Prof. 1998

 

Research staff

Prof. Bator Grażyna

Prof. Galewski Zbigniew

Dr. Czupiński Olaf

Dr. Piecha Anna

Dr. Szklarz Przemysław

Dr. Tarasiewicz Jolanta

Dr. Wojtaś Maciej

Chański Michał, M. Sc.

Jarek-Mikulska Urszula, M.Sc.

Owczarek Magdalena, M.Sc.

Płowaś Iwona, M.Sc.

 

 

Research topics

• Dielectric properties of molecular crystals and liquid crystals.

• Studies of phase transitions in ferroelectric and ferroelastic crystals.

• Searching for new polar materials.

• Liquid crystals – studies of polymorphism by means of thermo-optical analysis method (TOA)
and differentials scanning calorimetry (DSC).

• Studies of microscopic ferroelastic domain structure.

 

 

Special equipment

• Equipment for dielectric dispersion studies over frequency region 20–30 MHz in a wide temperature range (100–400 K)
precision RLC Meter HP 4285 and HP 4285A.

Pyroelectric effect in the temperature range between 100 and 400K (Electrometer Keithley 617).

• Equipment for studies of the linear thermal expansion of single crystals in the temperature range 90–500 K
(Thermomechanical Analyzer Perkin Elmer TMA-7).

 

 

Recent research achievements

 

The main goal of the investigations carried out in our laboratory is a search for new materials with interesting properties (mostly single crystals) from the group of the molecular-ionic salts like alkylammonium halogeno-antimonates(III and V) and halogenobismuthates(III). The studies are focused on ferroelectric or ferroelastic properties of materials. We exploit the following methods: dielectric measurements (in the wide frequency and temperature range) as well as the spectroscopic measurements (IR and Raman, in the wide temperature range), linear thermal expansion measurements and measurements of the spontaneous polarization in ferroelectrics (pyroeffect) The most important achievement in the recent years is a discovery of a new ferroelectric crystal: an imidazolium derivative in the family of halogenobismuthates(III), (C3H5N2)5Bi2Cl11, (Phys. Rev. B, 72, 104107, 2005) and studies on its physical properties. This material reveals ferroelectric properties below 166 K and its polarity is related to dynamics of the imidazolium cations, such a mechanism of ferroelectricity was proved on the basis of results obtained by means of the dielectric and crystallographic methods. In this salt a rare structure of the anionic sublattice, i.e. the discrete Bi2Cl115– biocathedra, was disclosed. Although the separate units of the anionic structure in this crystal are present no reorientational motions of them has been found and the anionic sublattice is rigid.

 

 

95

 

 

 

 

Selected papers:

1.       1.    Jakubas R., Piecha A., Pietraszko A., Bator G.
Structure and ferroelectric properties of (C3N2H5)5Bi2Cl11.
Phys. Rev., 2005, 72, 104107.

2.       Piecha A., Bator G., Jakubas R.
Critical slowing down of low-frequency dielectric relaxation in ferroelectric (C3N2H5)5Bi2Cl11.
J. Phys.: Condens. Matter, 2005, 17, L411–L417.

3.       Sawka-Dobrowolska W., Bator G., Sobczyk L., Pawlukojć A., Ptasiewicz-Bąk H., Rundlõf H., Jagielski P., Janik J. A., Krawczyk J., Nowina-Konopka M., Steinsvoll O., Grech E., Nowicka-Scheibe J.

Elastic, quasielastic and inelastic neutron scattering studies on the CT hexamethylbenzene-tetracyanoquinodimethane complex.
J. Chem. Phys., 2005, 123, 124305.

4.       Kulicka B., Kinzhybalo V., Jakubas R., Ciunik Z., Baran J., Medycki W.
Crystal structure and phase transition of 4-aminopyridinium tetrachlorobismuthate(III),
[4-NH2C5H4NH ][BiCl4 ], as studied by x-ray diffraction, dielectric, proton NMR and infrared spectroscopy.
J. Phys.: Condens. Matter, 2006, 8, 5087.

5.       Szklarz P., Gałązka M., Zieliński P., Bator G.
Study of phase transition in ferroelectric crystals [CH3NH3]3Bi2Cl11 (MAPCB) and [CH3NH3]3Bi2Br11 (MAPBB) by Nonlinear Dielectric Effect
Phys. Rev., 2006, 74, 184111

6.       Piecha A., Kinzhybalo V., Ślepokura K., Jakubas R.
Structural characterization, thermal and electric properties of imidazolium bromoantimonate(III): [C3H5N2]3[Sb2Br9].
J. Sol. State Chem. 2007, 180, 265.

7.       Wojtaś M., Zaleski J., Medycki W., Jakubas R.
Structure and properties of tris(tetramethylammonium)nonabromodiarsenate(III) [(CH3)4N]3[As2Br9].
J. Phys.: Condens.
Master, 2007, 19, 236221.

8.       Bator G., Jakubas R., Baran J.
Vibrational study of the structural phase transitionsin 4-aminopyridinium tetrachloroantimonate(III) (4-APCA) ferroelectric crystal by infrared spectroscopy.
Vib. Spectrosc., 2007, 45, 36.

9.       Piecha A. and Jakubas R.
Dielectric critical slowing-down in ferroelectric (C3N2H5)5Sb2Br11.
J. Phys. Condens. Matter 2007, 19, 621.

10.   Bator G., Prager M., Wischnewski A., Grech E., Pawlukojć A., Sobczyk L.
INS spectroscopic study of the 1:1 tetramethylpyrazine (TMP) squaric acid (H2SQ) complex.
Chem. Phys. 2007, 334, 148.