Induced polarized state in intentionally grown oxygen deficient KTaO3 thin films
authors Mota, DA; Romaguera-Barcelay, Y; Tkach, A; de la Cruz, JP; Vilarinho, PM; Tavares, PB; Moreira, JA; Almeida, A
nationality International
journal JOURNAL OF APPLIED PHYSICS
keywords STRONTIUM-TITANATE; SRTIO3; FERROELECTRICITY; PEROVSKITES; DISPERSION; TANTALATE; DEFECTS; OXIDE
abstract Deliberately oxygen deficient potassium tantalate thin films were grown by RF magnetron sputtering on Si/SiO2/Ti/Pt substrates. Once they were structurally characterized, the effect of oxygen vacancies on their electric properties was addressed by measuring leakage currents, dielectric constant, electric polarization, and thermally stimulated depolarization currents. By using K2O rich KTaO3 targets and specific deposition conditions, KTaO3-delta oxygen deficient thin films with a K/Ta = 1 ratio were obtained. Room temperature X-ray diffraction patterns show that KTaO3-delta thin films are under a compressive strain of 2.3% relative to KTaO3 crystals. Leakage current results reveal the presence of a conductive mechanism, following the Poole-Frenkel formalism. Furthermore, dielectric, polarization, and depolarization current measurements yield the existence of a polarized state below T-pol similar to 367 degrees C. A Cole-Cole dipolar relaxation was also ascertained apparently due to oxygen vacancies induced dipoles. After thermal annealing the films in an oxygen atmosphere at a temperature above T-pol, the aforementioned polarized state is suppressed, associated with a drastic oxygen vacancies reduction emerging from annealing process. (C) 2013 AIP Publishing LLC.
publisher AMER INST PHYSICS
issn 0021-8979
year published 2013
volume 114
issue 3
digital object identifier (doi) 10.1063/1.4813324
web of science category Physics, Applied
subject category Physics
unique article identifier WOS:000322202700078
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  impact metrics
times cited (wos core): 1
journal impact factor (jcr 2016): 2.068
5 year journal impact factor (jcr 2016): 2.103
category normalized journal impact factor percentile (jcr 2016): 60.204
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