abstract
In this work, we show that epitaxially strained SrTiO 3 - delta thin films, grown by ion-beam sputtering onto (001)Nb: SrTiO 3 substrates, exhibit a ferroelectric behavior. At the atomic-scale, through high -angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images, it was possible to identify the presence of polar nanoregions with non -trivial polar topological structures in the SrTiO 3 - delta film, which are induced through oxygen vacancies. To further confirm the presence of strained regions with a polar structure, Raman spectroscopy and high-resolution X-ray diffraction were employed and it was possible to confirm the presence of a tetragonal structure in the SrTiO 3 - delta film, with a tetragonality ratio ( c/a ) of 1.005. Scanning probe microscopy and macroscopic polarization-electric field hysteresis loops show ferroelectric behavior with maximum polarization of -1.5 mu C/cm 2 , remnant polarization of -0.4 mu C/cm 2 and coercive field of -0.3 MV/cm. This work opens a window for exploring novel polar topological effects in sub-10 nm thin film materials for non-volatile memory application.
keywords
DEFECT; POLARIZATION
subject category
Science & Technology - Other Topics; Materials Science
authors
Rodrigues, T; Silva, JPB; Figueiras, F; Soares, MR; Vilarinho, R; Moreira, JA; Çaha, I; Deepak, FL; Almeida, B
our authors
Fábio Gabriel Nazário Figueiras
Post-Doc Fellowship
Maria do Rosário Teixeira Soares
Laboratory OfficerGroups
acknowledgements
This work was supported by: (i) the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding Contract UIDB/04650/2020; (ii) the exploratory research project 2022.01740.PDTC (https://doi.org/10.54499/2022.01740.PTDC) , (iii) PTDC/NANMAT/0098/2020, (iv) 2022.03564 PTDC and (v) PT national funds FCT/MCTES, Fundacao para a Ciencia e Tecnologia and Ministerio da Ciencia, Tecnologia e Ensino Superior (PIDDAC) through the CICECO-Aveiro Institute of Materials. J. P. B. S. also thanks FCT for the contract under the Institutional Call to Scientific Employment Stimulus - 2021 Call (CEECINST/00018/2021-https://doi.org/10. 54499/CEECINST/00018/2021/CP2806/CT0016) .