Curriculum Vitae
Born August 18th, 1954 in Halle (Saale), Germany
| 1975-1980 |
Studies of physics at Martin-Luther-University Halle-Wittenberg, Germany |
| 1980 | Diploma thesis in solid state physics on "Nonlinear elastic, electromechanical
and dielectric properties in the vicinity of structural phase transitions" |
| 1980-1984 |
Scientific assistant at the Department of Physics, Martin-Luther-University
Halle-Wittenberg, |
| 1984 |
Doctoral thesis in solid state physics on "Nonlinearities of TGS-crystals with
defects". |
| since 1984 |
Research associate in Solid State Physics at the Department of Physics,
Martin-Luther-University Halle-Wittenberg |
| 1985 |
Dr.rer.nat. degree at Martin-Luther-University Halle-Wittenberg. |
| 1991-1998 | Member of the Sonderforschungsbereich SFB 185 (Nonlinear Dynamics) |
| 1992-1997 |
Project leader “Small signal amplification in a nonlinear series resonance
circuit with TGS-capacitor near a period-doubling bifurcation”
Ministry of Science and Technology (BMBF) |
Research interests
Nonlinear dynamics, especially bifurcations and chaos in nonlinear resonators and stochastic
resonance; investigation of nonlinear elastic, electromechanical, dielectric and pyroelectric
properties of ferroelectrics (bulk materials and thin films) by methods derived from nonlinear
dynamics; switching properties of ferroelectrics; phase transitions, especially ferroelectric phase
transitions
|
His Topic of Materials' Days 2009:
Nonlinear Effects in Nanoscaled Ferroelectrics and Possible Applications
Abstract:
Ferroelectrics are materials with a broad field of applications. This follows from the wide variety of
their physical properties, including high dielectric permittivity for the application in capacitors, high
piezoelectric coefficients for the conversion of mechanical influences into electric signals and vice
versa, good pyroelectric properties for application in infrared detectors, electrooptic effects for use
in light-modulators or displays, and polarization reversal (switching) caused by external electric
fields for the application in ferroelectric memories (FERAMs).
It is well known that most of the properties of ferroelectric materials exhibit nonlinear
characteristics. This means the response of the ferroelectric materials is not proportional to the
external impact.
These nonlinear effects become more and more important if the external influences like electric
field strengths or mechanical stresses are increased. On the other hand the miniaturization of
sensors, transducers and other elements produced on the basis of these materials leads to nonlinear
effects at external fields that would be considered as moderate from a macroscopic point of view.
Often this is considered as a drawback for applications. But sometimes such nonlinear properties
can be used as a basis for completely new principles of applications.
We demonstrate this by means of a nonlinear series resonance circuit with ferroelectric capacitor,
which can be tuned to chaotic behavior, well known from the theory of nonlinear dynamical
systems. A period doubling bifurcation on the route to chaos is used to construct a special sensor
combining both linear as nonlinear properties of the ferroelectric detector material.
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