Fabrication and physical properties of ferroelectrics confined in nanoporous materials
Zusammenfassung der Projektergebnisse
The fabrication and studies of ferroelectric materials within nanoporous matrices (porous glasses, artificial opals, zeolites, mesoporous materials of type MCM-41 and SBA-15) with characteristic sizes in the range of 0.7 to 100 nm could be carried out to a broad extent. NaNO2, BaTiO3, and other nanostructures were prepared. The main goal of the project consisted in studying size effects on phase transitions in ferroelectric nanostructures, viz. shifts of the phase transition temperatures, size-induced suppression of ferroelectric phase transitions, smearing out ofthe phase transitions and and the kinetics of the order parameter in confined ferroelectrics. These properties are related to changes in the microscopic parameters (local electric and magnetic field distribution, chemical bonding). This allowed to use various NMR methods, acoustic methods and other techniques (like small angle X ray scattering, dielectric measurements which could be realized in cooperation). The role of pore geometry (irregular three-dimensional pore network in porous glasses, regular pore lattices in artificial opals, zeolites and mesoporous materials, like MCM-41 and SBA 15, was investigated. The experimental results were compared with theoretical predictions on the basis of a phenomenological treatment of ferroelectric phase transitions in small particles and thin films. A deeper theoretical analysis, however, is still missing. For a deeper understanding of the behaviour of fine particles of BaTiO3 with particle diameters between 15 nm and 150 nm it was very helpful to investigate also barium titanate embedded in nanoporous materials. This comparison gave further insights into the question of size driven paraeletric-ferroelectric phase transition. For a better understanding of the melting behaviour in NaNO2, also Rochelle salt and the melting behaviour of metallic gallium and mercury in porous glasses were studied.
Projektbezogene Publikationen (Auswahl)
- Dielectric Parameters of Mesoporous Sieves Filled with NaNO2, In: Physics of the Solid State, 49 (2007) issue 4, pp. 791-795. In Russ.: Fiz. Tverd. Tela 49 , 4 (2007) 751-755
S. V. Baryshnikov, E. V. Charnaya, Cheng Tien, D. Michel, N. P. Andriyanova, and E. V. Stukova
- Dielectric and NMR studies of superionic Agl embedded in mesoporous silica matrices. Physics of the Solid State, 50 (2008) issue: 7, pp. 1342-1346. In Russ.: Fiz. Tverdovo Tela 50, issue 7 (2008) 1290-1294
S.V. Baryshnikov,, Cheng Tien, E. V. Charnaya, M. K. Lee, D. Michel, W. Böhlmann, and N. P. Andriyanova
- Dielectric properties of mesoporous sieves filled with NaNO2, Ferroelectrics, Volume 363 (2008), pp. 177-186
S.V. Baryshnikov, Cheng Tien, E. V. Charnaya, M. K. Lee, D. Michel, W. Böhlmann
- Investigation of Barium Titanate Nanoparticles by 137Ba NMR, Ferroelectrics 363 (2008) 215-226
P. Sedykh, J. Haase, D. Michel, and E. V. Charnaya
- Nature of the 23Na spin relaxation increase near the ferroelectric phase transition in bulk and confined sodium nitrite, Ferroelectrics, 366 (2008), pp. 177-186
Cheng Tien, E. V. Charnaya, M. K. Lee, S. V. Baryshnikov, D. Michel, and W. Böhlmann
- NMR studies of structure and ferroelectricity for Rochelle salt nanoparticles embedded into mesoporous sieves, J. Phys.: Condens. Matter, 20 (2008) issue: 21, 215205/1 - 215205/6
Cheng Tien, E. V. Charnaya, M. K. Lee, S. V. Baryshnikov, D. Michel, W. Böhlmann
- Superionic phase transition in Agl embedded in molecular sieves, J. Phys.: Condens. Matter, 20 (2008) issue 2, 025214 (5 pp.)
S.V. Baryshnikov, Cheng Tien, E. V. Charnaya, M. K. Lee, D. Michel, W. Böhlmann, and N. P. Andriyanova
- Ferroelectric phase transition in barium titanate nanoparticles, Phys. Rev. B 79, 1341191-1341198 (2009)
P. Sedykh and D. Michel
- Phase transitions in K1-xNaxNO3 embedded into molecular sieves, J. Phys.: Condens. Matter 21 (2009)325902
S V Baryshnikov, E V Charnaya, A Yu Milinskiy, E V Stukova, Cheng Tien and D Michel
- Ferroelastic phase transition in LiCsSO4 embedded into molecular sieves, Physics Letters A 375 (2010) 183-186
B. F. Borisov, E. V. Charnaya, S. V. Baryshnikov, A. L. Pirozerskii, A. S. Bugaev, Cheng Tien, M. K. Lee, D. Michel
- Size effects in fine barium titanate particles, Ferroelectrics, Ferroelectrics 400 (2010) 135-143
P. Sedykh, D. Michel, E. V. Charnaya, J. Haase
- Stabilization of ferroelectricity in KNO3 embedded into MCM-41 molecular sieves, Physica B 405 (2010) 3299-3302
S.V. Baryshnikov, E.V. Charnaya, A.Yu. Milinskiy, Yu.A. Shatskaya, C. Tien, D. Michel
