Dresden 2006 – wissenschaftliches Programm

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DF: Dielektrische Festkörper

DF 2: Dielectric and Ferroelectric Thin Films and Nanostructures I

DF 2.1: Hauptvortrag

Montag, 27. März 2006, 14:30–15:10, M{\"U}L Elch

Size effects in ferroelectric nanostructures — •Andreas Rüdiger — Center of Nanoelectronic Systems for Information Technology, Institute of Solid State Research, Research Center Jülich, 52425 Jülich, Germany

Ferroelectrics are among the most advanced candidates for non-volatile memory applications. They are also widely used in pyroelectric sensors and piezoelectric actuators. As current integration techniques are driving the dimensions towards 10nm lateral extension and only a few unit cells height, the analogy to ferromagnetism raises the question if a lower size limit also exists for ferroelectrics. Earlier studies on free particles neglected electromechanical constraints imposed by conductive substrates and rather determined a pyroelectric limit (i.e. the size-driven transition into a centrosymmetric phase). Our results of piezoelectric force microscopy on e.g. ferroelectric BaTiO₃ nanoislands indicate structural and functional integrity well below the critical volume of free particles. So far, there is no evidence of a size limit in ferroelectric nanoparticles on conducting substrates. We highlight the impact of the aforementioned electromechanical boundary conditions on ferroelectricity and discuss composition and time-scale as possible origins of a critical size below 10 nm.