Berlin 2012 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 29: High-k and low-k dielectrics (joint session with DF)
DS 29.1: Vortrag
Mittwoch, 28. März 2012, 09:30–09:50, EB 407
High dielectric constants due to charge order induced electrical heterogeneity — •Stephan Krohns1, Pit Sippel1, Holger Kirchhain1, Stefan Riegg1, Peter Lunkenheimer1, Armin Reller2, and Alois Loidl1 — 1Experimental Physics V, University of Augsburg — 2Resource Strategy, University of Augsburg
One of the most imminent challenges of modern materials science is the development of new materials with less critical elements that have comparable or better functionalities than those currently used. We illustrate an interdisciplinary approach by applying it to the prototypical example of materials with extremely high dielectric constant to validate the innovative potential in a very early stage of research.1
Not only the validation of the economic and technical potential of high dielectric constant materials are in the focus of interest, but also the mechanisms generating this dielectric phenomena. Most of the materials exhibiting those effects, among them numerous transition-metal oxides2, have complex ground states emerging from strong electronic correlations. La15/8Sr1/8NiO4 for example shows a very high dielectric constant up to gigahertz frequencies at room temperature and it seems that charge order induced electrical heterogeneity can be the origin. To scrutinize that, we also thoroughly investigate the structural, magnetic and dielectric properties of various isostructural La2−x(Ba,Ca,Sr)xNiO4 compounds especially emphasizing the contribution of electronic phase separation to the permittivity.
[1] S. Krohns et al., Nat. Mat. 10, 899 (2011). [2] P. Lunkenheimer et al., Eur. Phys. J. Special Topics 180, 61 (2010).