Regensburg 2013 – scientific programme
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DS: Fachverband Dünne Schichten
DS 20: High- and Low-k-Dielektrics (jointly with DF)
DS 20.1: Talk
Wednesday, March 13, 2013, 09:30–09:50, H11
Dielectric signature of charge order in lanthanum nickelates — •Pit Sippel, Stephan Krohns, Peter Lunkenheimer, and Alois Loidl — Experimental Physics V, University of Augsburg, Germany
The technical progress of electronics requires new materials which have enhanced electrical properties, are cheaper, and are composed of non-scarce elements. In the last years charge-ordered nickelates, due to their extraordinary high-dielectric constant, have been found to be promising materials for the use as dielectrics in capacitive circuit elements [1]. However, the mechanism giving rise to their high dielectric constants is still under debate. Therefore we have performed a thorough structural, magnetic, and dielectric investigation of various isostructural La2−x(Ba,Ca,Sr)xNiO4 compounds. For commensurably charge-ordered nickelates, a correlation between electronic phase separation and the permittivity is observed [2]. The dielectric spectra of these compounds show a superposition of two relaxational processes. The stronger one is most probably related to a non-intrinsic effect. The second one seems to originate from an intrinsic process. To gain further insight into the origin of the mechanisms leading to the observed relaxation spectra, ceramics and singlecrystalline samples have been examined.
[1] S. Krohns et al., Nat. Mat. 10, 899 (2011).
[2] P. Sippel et al., Eur. Phys. J. B 85, 235 (2012).