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DF: Dielektrische Festkörper

DF 5: Dielektrische und ferroelektrische dünne Schichten und Nanostrukturen I

DF 5.2: Vortrag

Montag, 7. März 2005, 10:40–11:00, TU TC6

Structure of nanocrystalline BaTiO(3)-films prepared at different temperatures. — •Kesav Reddy¹, Dieter Mergel¹, Stefan Reuter¹, Volker Buck¹ und Martin Sulkowski² — ¹AG Dünnschicht-Technologie, Universität Duisburg-Essen, 45117 Essen — ²Institut für Umwelt-Analytik, Universität Duisburg-Essen

BaTiO(3) films were prepared by rf magnetron sputtering at substrate temperatures between 450^∘C and 750^∘C and analyzed by means of XRD, optical transmittance and Raman spectroscopy.

The films prepared at 450^∘C exhibit a distinct close-range order but no higher-order XRD reflexes. The films prepared below or above 650^∘C grow preferentially in (100)- or (110)-direction, respectively. The position of the XRD-reflexes is closest to those of the hexagonal phase. Raman spectra exhibit peaks of both the hexagonal and cubic structure.

These results are discussed on the basis of a structural model of nanocrystallites comprising the stacking of close-packed planes (111 in the cubic structure) with a high degree of twinning.