April 2013

Journal

Effect of stoichiometry on the dielectric properties and soft mode behavior of strained epitaxial SrTiO3 thin films on DyScO3 substrates

By:
Lee, Che-Hui; Skoromets, Volodymyr; Biegalski, Michael D; Lei, Shiming; Haislmaier, Ryan; Uecker, Reinhard; Bernhagen, M; Xi, Xiaoxing; Gopalan, V; Marti, Xavier; Kamba, Stanislav; Kuzel, Petr; Schlom, Darrell
Journal Name:
Applied Physics Letters
Page Number:
82905
Volume:
102
Issue Number:
8
Publication Date:
April 2, 2013
View DOI Listing:
https://doi.org/10.1063/1.4793649

Abstract

The effect of stoichiometry on the dielectric properties and soft mode behavior of strained epitaxial Sr1-xTiO3 films grown on DyScO3 substrates is reported. Direct comparisons between nominally stoichiometric and non-stoichiometric films have been performed through measurements of lattice parameters, temperature-dependent permittivities, second harmonic generation, and terahertz dielectric spectra. The nominally stoichiometric film shows dispersion-free low-frequency permittivity with a 23 sharp maximum and pronounced soft mode behavior. Our results suggest that strained perfectlystoichiometric SrTiO3 films should not show relaxor behavior and that relaxor behavior emergesfrom defect dipoles that arise from non-stoichiometry in the highly polarizable strained SrTiO3 matrix