Berlin 2005 – wissenschaftliches Programm
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DF: Dielektrische Festkörper
DF 3: FV-internes Symposium „Polare Polymere und Ferroelektrete“
DF 3.3: Vortrag
Samstag, 5. März 2005, 09:30–09:50, TU C130
Three-dimensional mapping of polarization profiles in ferroelectric polymers with thermal pulses — •Axel Mellinger1, Rajeev Singh1,2, Michael Wegener1, Werner Wirges1, Reimund Gerhard-Multhaupt1, and Sidney B. Lang3 — 1Department of Physics, University of Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany — 2Department of Electronics & Communication, University of Allahabad, Allahabad, (U.P.)-211002, India — 3Department of Chemical Engineering, Ben-Gurion University of the Negev, P.O.B. 653, 84105 Beer Sheva, Israel
The probing of polarization and space-charge depth profiles via thermal methods has been an area of ongoing research for nearly 30 years. Recent thermal-pulse measurements with state-of-the-art equipment have demonstrated that individual data points can be acquired on a timescale of seconds [1]. Using a focused laser beam as excitation source thus opens up the possibility of obtaining high-resolution, large-area three-dimensional polarization maps. This technique was tested on films of ferroelectric polyvinylidene fluoride poled with patterned electrodes, yielding a lateral resolution of 38 µm and a near-surface depth resolution of less than 0.5 µm. At larger depths, the lateral resolution is limited by fast thermal diffusion in the metal electrode rather than the laser spot size. Finite-element solutions of the heat-conduction equation show a transient temperature distribution differing significantly from the one-dimensional case, with potential impacts on the data-analysis procedure.
[1] A. Mellinger, R. Singh and R. Gerhard-Multhaupt, Rev. Sci. Instr. 76 (in press), 2005.