Polar phonons in polycrystalline SrTiO3 thin films: The role of the substrate
authors Okhay, O; Tkach, A; Nuzhnyy, D; Petzelt, J; Vilarinho, PM
nationality International
journal FERROELECTRICS
author keywords Thin films; sol-gel; thermal expansion; stress; strain; dielectric properties
keywords INDUCED FERROELECTRICITY; PHASE-TRANSITION; TEMPERATURE; RESONANCE; MODES
abstract Recently we have demonstrated that out-of-plane dielectric properties of polycrystalline SrTiO3 (ST) films depend on the strain/stress induced by the substrates due to thermal expansion misfit. Here, we present a complementary infra-red (IR) spectroscopy investigation of the role of Al2O3 and MgO substrates on the lattice dynamics and in-plane dielectric properties of ST thin films also prepared by sol-gel. We verify that ST films deposited on Al2O3 substrates, being under a tensile stress, present the soft mode behaviour similar to that of ST single crystals, deviating just below 150 K. In contrast, ST films deposited on MgO substrates, being under compressive stress, have higher soft mode frequency from 10 to 300 K. It is thus proved that for polycrystalline ST films the intrinsic in-plane relative permittivity may be tuned through an induced stress state.
publisher TAYLOR & FRANCIS LTD
issn 0015-0193
year published 2018
volume 532
issue 1
beginning page 89
ending page 99
digital object identifier (doi) 10.1080/00150193.2018.1499407
web of science category Materials Science, Multidisciplinary; Physics, Condensed Matter
subject category Materials Science; Physics
unique article identifier WOS:000458445000013
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journal analysis (jcr 2017):
journal impact factor 0.728
5 year journal impact factor 0.590
category normalized journal impact factor percentile 11.956
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