Hamburg 2001 – scientific programme

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DF: Dielektrische Festkörper

DF 7: Ferroelektrische Schichten, Nanostrukturen und Keramiken

DF 7.4: Fachvortrag

Thursday, March 29, 2001, 10:50–11:10, S18/19

Structural and dielectric properties of BaTiO₃/SrTiO₃-multilayers — •Wolfgang Haessler¹, Koebernik G.¹, Kundzins K.², and Weiss F.³ — ¹IFW Dresden — ²University Riga, Latvia — ³INPG Grenoble, France

Dielectric superlattices are characterized by the structural variability of the film periodicity additional to the stochiometry. They have interesting dielectric properties different from the solid solutions of the same overall composition.

In this paper the structural and dielectric properties of BaTiO₃ / SrTiO₃-superlattices prepared by pulsed laser deposition on single crystalline SrTiO₃-substrates and on Si/Pt-heterostructures are characterized in comparison to a (Ba_0,5Sr_0,5)TiO₃ solid solution. The films were characterized using X-ray diffraction, SEM and dielectric measurements.

We measured the dielectric constant in the wide temperature range from 30 K up to 700 K as well as the hysteresis behaviour of our films.

The variation of the film thickness in the range from 500 nm down to 30 nm and of the monolayer thickness between 30 nm and 1.2 nm shows that the dielectric constant of the multilayers is always lower in comparison to the solid solutions, the thickness dependence.

The influence of an external bias field on the susceptibility of multilayer films is weaker then for monolayes. The temperature dependence of the dielectric constant of BaTiO₃ / SrTiO₃-superlattices shows a broad peak and the peak-temperature is shifted slightly to lower values.