Assessment of Strain Relaxation and Oxygen Vacancy Migration near Grain Boundary in SrTiO3Bicrystals by Second Harmonic Generation

Onur Kurt, Tony Le, Sulata K. Sahu, Clive A. Randall, Yuhang Ren*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Mesoscopic structural distortions that result from ionic space charge accumulation near a grain boundary have impacts on the electrical conductivity and optical properties of perovskite oxides. Here, we report on our study that address the correlation between strain distribution and oxygen vacancy migration and pile up in undoped SrTiO3 (STO) bicrystals using local probing via the optical second harmonic generation (SHG) under electrical degradation. Comprehensive SHG measurements were taken near the grain boundary in both reflection and transmission geometries. While we confirmed a 10°-tilted grain boundary and an anisotropic strain distribution in the pristine bicrystal, we also revealed oxygen vacancies are confined and accumulated near the strain-imposed boundary in the electrically degraded bicrystal. During the degradation process, oxygen vacancies migrate, and electronic charge can be injected. With the grain boundary acting as a barrier to the oxygen vacancy migration, there can be a strain gradient on both sides of the grain boundary, and also with the charge an internal electrical field is developed. Our results strongly indicate that oxygen vacancies are preferentially formed and are segregated at the grain boundary where the strain accumulates and impedes oxygen vacancy diffusion under a concentration gradient.

Original languageEnglish
Pages (from-to)11892-11901
Number of pages10
JournalJournal of Physical Chemistry C
Issue number22
Publication statusPublished - 4 Jun 2020
Externally publishedYes

Bibliographical note

Publisher Copyright:
Copyright © 2020 American Chemical Society.


This work was supported in part by the Air Force Office of Scientific Research (Grant Nos. FA9550-17-1-0339 and FA9550-17-1-0342).

FundersFunder number
Air Force Office of Scientific ResearchFA9550-17-1-0342, FA9550-17-1-0339


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